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  • How to configure CISCO switch 2960 for port-based address allocation on a single port only?

    - by Jack
    CISCO 2960 allows you to configure so-called Port-Based address allocation. It makes the switch to associate IP address it is giving out via DHCP with port-identifier, which is random, switch created identifier. In practice it means that any machine connected to such configured port will always get the same IP address, regardless of what that machine's MAC address is. I want to have that feature configured on --some ports-- only. But no matter what commands I try it seems that this can only be done for all ports, all for none. Even though CISCO manual seems to indicate there's both global and per-port command to enable that. Here are relevant commands from CISCO manual: configure terminal ip dhcp use subscriber-id client-id (this configures the DHCP server to globally use the subscriber ID as the client ID on all incoming DHCP messages) interface FastEthernet0/1 ip dhcp server use subscriber-id client-id (Optional: Configures the DHCP server to use the subscriber ID as the client ID on all incoming DHCP messages on the interface) but it appears if I configure only per-interface than there's no effect at all, if I configure globally and per interface - CISCo behaves as if all ports were configured to use that feature. Any ideas?

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  • Relaying to tech "support" that computer is actually broken.

    - by Sion
    First some background: I have a Dell Inspiron 15R M050, it is still under the Dell limited warranty and the Best Buy Extended warranty. I am currently dual booting Debian Squeeze and Windows 7, the only reason I go into Windows is to play video games specifically steam games. Issue: When I play my games in Windows I am capable of playing for anywhere from 5 minutes to 2 hours before I suffer a hard-lock. I cannot alt-tab, ctrl-alt-delete, ctrl-shift-escape do anything for 2-3 minutes. After this hard-lock period everything runs fine, I can continue the game for probably another hour at least before I suffer another lock. Games: Borderlands, Splinter Cell: Chaos Theory, Starcraft 2, Garrys Mod What I have tried: Running the diagnostic suite in the dell bios, restoring the OEM Windows recovery partition on the HD, fresh installing Windows 7 Professional, updating BIOS, Calling tech support and having them run a software Hardware Diagnostics suite. The question: I think from the research that I have performed that it might be a lack of thermal paste on the CPU, would I be able to go to Best Buy and have them do a hardware diagnostic from the hardware level then have them be able to tell Dell that there is a hardware issue? Or would there be a different problem?

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  • vmware player won't run on CentOS due to missing /dev/vmmon, what could be the problem?

    - by Graphics Noob
    So I've tried installing vmware player 3.1.4 and 3.1.3 and both times had the same problem, when I try to load a VM I get the error "Could not open /dev/vmmon". When I ls /dev/ I can see there is no "vmmon" device present. When I try running: sudo /etc/init.d/vmware start I get the output: Starting VMware services: VMware USB Arbitrator [ OK ] Virtual machine monitor [FAILED] Virtual machine communication interface [ OK ] VM communication interface socket family [ OK ] Blocking file system [ OK ] Virtual ethernet [FAILED] which shows that the Virtual Machine Monitor fails to load. I tried following the advice on this site and ran vmware-modconfig --console --install-all I notice during the compilation there are no errors, but at the end I get the message: Starting VMware services: VMware USB Arbitrator [ OK ] Virtual machine monitor [FAILED] Virtual machine communication interface [ OK ] VM communication interface socket family [ OK ] Blocking file system [ OK ] Virtual ethernet [ OK ] Unable to start services Out of curiousity I tried: sudo /sbin/insmod /lib/modules/2.6.18-238.9.1.el5xen/misc/vmmod.ko But got the error message: insmod: error inserting 'vmmon.ko': -1 Invalid module format I have a feeling this may be the root of the problem, but I don't know what could be causing it or how to fix it.

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  • RTNETLINK answers: File exists... maybe because assigned a new mac adress

    - by steven
    I got a "RTNETLINK answers: File exists Failed to bring up eth0:1" on "ifup eth0:1". I suspect it happens because i assigned a new mac adress in my VM's network adapter. Can you tell me how to fix the issue? My configuration looks like this: # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 allow-hotplug eth0 iface eth0 inet static address 192.168.1.80 netmask 255.255.255.0 gateway 192.168.1.1 dns-nameservers 192.168.1.1 # Alias being connected to 192.168.10.x Network auto eth0:1 allow-hotplug eth0:1 iface eth0:1 inet static address 192.168.10.83 netmask 255.255.255.0 gateway 192.168.10.10 dns-nameservers 192.168.10.1 Why do I get "RTNETLINK answer: File exists.." suddenly? I worked with this configuration before without problems. All i did in the past is to renew the adapters mac adress. At the moment I am connected to the 192.168.10.x Network and if I do /etc/init.d/networking stop /etc/init.d/networking start then i got "RTNETLINK [...] falied to bring up eth0:1" but the strage thing is that i am able to connect to 192.168.10.83 via ssh from my host machine. But I cannot reach the internet from the debian client. I hope it is clear what my problem is, now. update if i change my /etc/network/interfaces like this then "ifup eth0" fails, too with the same error! # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 allow-hotplug eth0 iface eth0 inet static address 192.168.10.83 netmask 255.255.255.0 gateway 192.168.10.10 dns-nameservers 192.168.10.1 with verbose option enabled i got: Configuring interfache eth0=eth0 (inet) run-parts --verbose /etc/network/if-pre-up.d ip addr add 192.168.10.83/255.255.255.0 broadcast 192.168.10.255 dev eth0 label eth0 RTNETLINK answers: File exists Failed to bring up eth0. same if i type this manually: ip addr add 192.168.10.83/255.255.255.0 broadcast 192.168.10.255 dev eth0 label eth0

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  • What is causing ocassional white windows on my Mac?

    - by user63333
    Hello. I'm having a very strange problem with my Mac lately. When I'm working in an app and a new window pane or sheet is displayed, sometimes it comes up completely white. Once an app is having these problems, it will continue to bring up a blank screen for that particular window (although other windows work fine). After the app is relaunched, the window is fine again. What I'm noticing that's very strange is that although the interface turns completely white, the functions of the interface are still available. So I have to "navigate blindly" around the interface, until I can relaunch. This occurs throughout the operating system. Screenshots: This is what happened when I tried opening the File menu in Lightroom app. What happened to me on Lynda.com (in Firefox) after selecting the "Software..." dropdown. (All other dropdowns were fine. Reloading the page fixed it.) When I was decompressing a file, The Unarchiver launched and opened this white window. It still decompressed the file. This is what happened one time when I opened Finder (with TotalFinder) to my Downloads folder. This is something I've never seen before. This just started happening lately. What could be the problem? Thanks for your help. NOTE: since new users are not allowed to post images, just image blank white interface elements. And since new users also aren't allowed to post more than one link, here's the first screenshot:

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  • Xen Bridge only working when IP Assigned

    - by m.sr
    Hey! Just had an (in my sense) obscure situation. I have a Xen Server with bridged networking. Everything works fine since month. A while ago i configuresd a second bridge. only some DomUs get an channel on this bridge - my Dom0 doesn't need to / should'nt use this bridge. So just 5 minutes ago while rebooting the xen host (because of an other problem with the UPS) i decided to removed the fixed ip from the the interface of the Dom0 which belongs to the second bridge. So after reboot i noticed that none of the interfaces on the second bridge is available. I couldn't find a problem. Everything was just like before the reboot, except the interface of the Dom0 had no IP address. After a while i tried to give the DomO interface of this bridge an IP again and ... BOOM ... everything is up and running again! WTF? Why is it important to have the interface of a bridge configured in the Dom0? Even when confiugured 'wrong' (complitely different netowkr settings as the network really hanging on the bridge) everythjing works fine ... I don't get it. Could please someone explain? Tnaks a lot!

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  • esx5 debian VM vlan setup

    - by Kstro21
    i have a server with ESX5, have a switch with about 20 vlans, this is how setup the trunk port interface GigabitEthernet0/1/1 description ToOper port link-type trunk undo port trunk allow-pass vlan 1 port trunk allow-pass vlan 2 to 14 stp disable ntdp enable ndp enable bpdu enable then, i created a standar switch(sw1) using the vSphere Client, the VLAN ID is set to All (4095), i also created a VM with Debian 6, with a NIC connected to sw1, now, i want to configure this NIC for a selected group of vlans auto vlan10 iface vlan10 inet static address 11.10.1.0 netmask 255.255.255.224 mtu 1500 vlan_raw_device eth0 auto vlan14 iface vlan14 inet static address 11.10.1.65 netmask 255.255.255.248 mtu 1500 vlan_raw_device eth0 so, when i restart the network using /etc/init.d/networking restart, i got this error Reconfiguring network interfaces...SIOCSIFADDR: No such device vlan14: ERROR while getting interface flags: No such device SIOCSIFNETMASK: No such device SIOCSIFBRDADDR: No such device vlan14: ERROR while getting interface flags: No such device SIOCSIFMTU: No such device vlan14: ERROR while getting interface flags: No such device Failed to bring up vlan14. done. this is just part of the error, so, my questions is: is this possible?, i mean, what i'm trying to achieve using ESX Virtual Machines, VLANS, etc is this a Debian problem? can be solved? i've read about a file named z25_persistent-net.rules in Debian but it doesn't exist in my installation. in the In the vSphere Networking for ESX5 guide, you can read: If you enter 0 or leave the option blank, the port group can see only untagged (non-VLAN) traffic. If you enter 4095, the port group can see traffic on any VLAN while leaving the VLAN tags intact. So, in theory, it should work, right? Hope you can help me up with this one Thanks

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  • RPC Server Unavailable on Hyper-V cluster when moving resources after the host adapter has failed

    - by Doug Luxem
    On a Windows 2008 R2 SP1 cluster running Hyper-V, a lost network connectivity on the primary host interface. The interface was rapidly flapping up and down, and this was later determined to be caused by a faulty switch port. As this was a clustered server, the host interface was not fault tolerant (seeing as how the whole server was fault tolerant), so connectivity to the host was going up and down. The Hyper-V guests were completely unaffected by the network outage as they used a dedicated trunk on the server separate from the host interface. Additionally, dedicated interfaces for the cluster and live migration networks were fine. In order to diagnose the server, I tried to move all resources (Hyper-V Guests) to other nodes through Failover Cluster Manager. These moves failed with an error RPC Server Unavailable. The only way to move resources was by shutting down the guests, stopping the cluster service on the Node A, allowing other nodes to take ownership of the resources, and restarting the guests. A few other notes: All nodes have Client for MS Networks and File & Printer Sharing enabled on the Cluster and LM networks. Node A was accessible over cluster and LM networks from other nodes (these are private, cluster-only networks); pingable, CIFs, etc. Accessing \\NODEA is done over the Host adapters, as you would expect in this case and is the reason for the RPC Server Unavailable error with that adapter being down. My questions here are - Is there a way to still use Live Migration in a failure scenario such as this to prevent shutting down the Hyper-V guests? How can the network be reconfigured in the future so that the cluster service attempts to use the cluster and/or live migration networks to issue the RPC requests?

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  • Vmware Workstation, Win7 host, Ubuntu guests with Nat + Host-only networks but they cannot connect to the Internet

    - by Ikon
    I have a Win7 host machine with Vmware Workstation. In the workstation I have 3 Ubuntu installed. All 3 Ubuntu guests have a Nat network - to access the internet without asking the router for a local address - and a Host-only network - to connect all Ubuntu quests and the host in a private network for internal communication, without touching the router. When I try to make any of the Ubuntu quests to get data from the internet - assuming that they would figure out that the Nat-ed interface can access the requested data - they fail and report that there is no route to my query. If I disconnect the 2nd interface on the Ubuntu guests with the Host-only network and restart networking, they start to know the route to the internet. Odd, during the installation of the guests they asked which of the 2 given interfaces - with Nat and Host-only config - should be used to get updates during installation and they oddly managed to get the updates. Not so after the installation has finished and rebooted. I have checked the Virtual Network Editor that the Nat interface should use my real network card to access the net, so there should be no problem. I wish not to use the router's dhcp service to give the Ubuntu quests an address, and also I don't want the guests to be accessable from the local network directly, but only by the host - that's the Host-only network is for. Any suggestions? Edit: 192.168.189.0 is the Nat interface and 192.168.7.0 is the Host-only. $ route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.7.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 192.168.189.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 0.0.0.0 192.168.189.2 0.0.0.0 UG 100 0 0 eth0

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  • Using a nat rule to translate 80/443 traffic to web server, but internal users cannot access it using external ip/domain name

    - by Josh
    I am using Cisco ASDM for ASA I have my internal network called soa. My outside interface is called outside. Let's say my outside IP given to me by my ISP isp is y.y.y.y I have a web server inside my network with a static ip of x.x.x.110. I have configured 2 static nat rules (one for http the other for https). Source is x.x.x.110. Interface is outside, service (http or https). Maybe I am doing this wrong, but when I run the packet tracer, I choose outside interface and for the source IP I used 8.8.8.8 and the destination ip is my outside IP address, y.y.y.y When I run that, it shows the packet traversing successfully, using 9 steps. For my other test, I switch to the soa interface, input an ip on that network, and leave the destination the same. This test comes up with 2 steps and then fails on my access list. When I see the rule that fails, it is my catch all which is source: any desitnation: any, service: ip action: deny. What rule do I need to make to allow my soa network access to go out and come back in by my external IP addess (using a domain name attached to that ip in my dns, of course)?

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  • VPN into multiple LAN Subnets

    - by Rain
    I need to figure out a way to allow access to two LAN subnets on a SonicWall NSA 220 through the built-in SonicWall GlobalVPN server. I've Googled and tried everything I can think of, but nothing has worked. The SonicWall NSA management web interface is also very unorganized; I'm probably missing something simple/obvious. There are two networks, called Network A and Network B for simplicity, with two different subnets. A SonicWall NSA 220 is the router/firewall/DHCP Server for Network A, which is plugged into the X2 port. Some other router is the router/firewall/DHCP server for Network B. Both of these networks need to be managed through a VPN connection. I setup the X3 interface on the SonicWall to have a static IP in the Network B subnet and plugged it in. Network A and Network B should not be able to access each other, which appears the be the default configuration. I then configured and enabled VPN. The SonicWall currently has the X1 interface setup with a subnet of 192.168.1.0/24 with a DHCP Server enabled, although it is not plugged in. When I VPN into the SonicWall, I get an IP address supplied by the DHCP Server on the X1 interface and I can access Network A remotely although I do not have access to Network B. How can I allow access to both Network A and Network B to VPN clients although keep devices on Network B from accessing Network A and vice-versa. Is there some way to create a VPN-only subnet (something like 10.100.0.0/24) on the SonicWall that can access Network A and Network B without changing the current network configuration or allowing devices on both netorks "see" each other? How would I go about setting this up? Diagram of the network: (Hopefully this kind of helps) WAN1 WAN2 | | [ SonicWall NSA 220 ]-(X3)-----------------[ Router 2 ] | | (X2) 192.168.2.0/24 10.1.1.0/24 Any help would be greatly appriciated!

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  • Debian Wheezy IPv6 isn't configured with ifup post-up hook

    - by aef
    We recently set up a server on Debian Wheezy Beta 3 (x86_64) which has a native IPv6 connection. We configured the eth0 interface to get the IPv6 configuration through some post-up hook commands in /etc/network/interfaces. The result is, that after the booting the system up, there is only IPv4 and an auto-configured link-local IPv6 address configured on the interface, as if the command has never been executed. When we additionally place the commands after the call to ifup -a inside the /etc/init.d/networking init script, everything works as expected and we have a fully configured interface after booting up. This is quite an ugly way to configure the interface. What are we doing wrong with the ifup post-up hooks? Or is this a bug? The section from /etc/network/interfaces looks like this (IP-addresses changed): allow-hotplug eth0 iface eth0 inet static address 1.2.3.1 netmask 255.255.255.192 network 1.2.3.0 broadcast 1.2.3.63 gateway 1.2.3.62 dns-nameservers 8.8.8.8 dns-search mydomain.tld post-up ip -6 addr add 2001:db8:100:3022::2 dev eth0 post-up ip -6 route add fe80::1 dev eth0 post-up ip -6 route add default via fe80::1 dev eth0 I also tried it in this alternative way: auto eth0 iface eth0 inet static address 1.2.3.1 netmask 255.255.255.192 network 1.2.3.0 broadcast 1.2.3.63 gateway 1.2.3.62 dns-nameservers 8.8.8.8 dns-search mydomain.tld iface eth0 inet6 static address 2001:db8:100:3022::2 netmask 64 gateway fe80::1 What we added to /etc/init.d/networking: … case "$1" in start) process_options check_ifstate if [ "$CONFIGURE_INTERFACES" = no ] then log_action_msg "Not configuring network interfaces, see /etc/default/networking" exit 0 fi set -f exclusions=$(process_exclusions) log_action_begin_msg "Configuring network interfaces" if ifup -a $exclusions $verbose && ifup_hotplug $exclusions $verbose # Our additions ip -6 addr add 2001:db8:100:3022::2 dev eth0 ip -6 route add fe80::1 dev eth0 ip -6 route add default via fe80::1 dev eth0 then log_action_end_msg $? else log_action_end_msg $? fi ;; …

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  • How to set a static route for an external IP address

    - by HorusKol
    Further to my earlier question about bridging different subnets - I now need to route requests for one particular IP address differently to all other traffic. I have the following routing in my iptables on our router: # Allow established connections, and those !not! coming from the public interface # eth0 = public interface # eth1 = private interface #1 (10.1.1.0/24) # eth2 = private interface #2 (129.2.2.0/25) iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT iptables -A INPUT -m state --state NEW ! -i eth0 -j ACCEPT iptables -A FORWARD -i eth0 -o eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT iptables -A FORWARD -i eth0 -o eth2 -m state --state ESTABLISHED,RELATED -j ACCEPT # Allow outgoing connections from the private interfaces iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT iptables -A FORWARD -i eth2 -o eth0 -j ACCEPT # Allow the two private connections to talk to each other iptables -A FORWARD -i eth1 -o eth2 -j ACCEPT iptables -A FORWARD -i eth2 -o eth1 -j ACCEPT # Masquerade (NAT) iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE # Don't forward any other traffic from the public to the private iptables -A FORWARD -i eth0 -o eth1 -j REJECT iptables -A FORWARD -i eth0 -o eth2 -j REJECT This configuration means that users will be forwarded through a modem/router with a public address - this is all well and good for most purposes, and in the main it doesn't matter that all computers are hidden behind the one public IP. However, some users need to be able to access a proxy at 192.111.222.111:8080 - and the proxy needs to identify this traffic as coming through a gateway at 129.2.2.126 - it won't respond otherwise. I tried adding a static route on our local gateway with: route add -host 192.111.222.111 gw 129.2.2.126 dev eth2 I can successfully ping 192.111.222.111 from the router. When I trace the route, it lists the 129.2.2.126 gateway, but I just get * on each of the following hops (I think this makes sense since this is just a web-proxy and requires authentication). When I try to ping this address from a host on the 129.2.2.0/25 network it fails. Should I do this in the iptables chain instead? How would I configure this routing?

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  • Same native and tagged vlan possible on Redhat?

    - by Chris Phillips
    Hi guys and gals, I'm looking at implementing a systems using a number of tagged and a native vlan connected to a server over a a/p bonded interface. The untagged vlan is for physical machine access, the tagged vlans are connected to bridges and then to QEMU VM's inside the machine. Hopefully this plan is fine, but I'm trying to implement a crippled version of this in a dev environment due to a lack of underlying network config in this location where I just have the same single vlan delivered to the machine on a tag AND plain. I'm nto clear if this is going to work (and that I should just be confident that it will work using different vlans) as I'm seeing odd things like a vm is arping out over the vlan out to the core switch, but the arp reply is coming back on the untagged interface. Now an ARP reply is unicast right? So it's a deliberate thing to send the ARP response on the untagged interface, and not a case that a broadcast response isn't being passed on the tagged side... i.e. there's some underlying logic pushing it that way. Something about the MACs somehow? This is on a CentOS 5.5 machine, vlan's from vconfig. (I've seen reference to the Linux mac-vlan project work, but that's not available here by default.) so 1) Should having the SAME vlan tagged and untagged work? 2) Will different tagged vlans to the untagged interface work nice and easily?

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  • ASA access lists and Egress Filtering

    - by Nate
    Hello. I'm trying to learn how to use a cisco ASA firewall, and I don't really know what I'm doing. I'm trying to set up some egress filtering, with the goal of allowing only the minimal amount of traffic out of the network, even if it originated from within the inside interface. In other words, I'm trying to set up dmz_in and inside_in ACLs as if the inside interface is not too trustworthy. I haven't fully grasped all the concepts yet, so I have a few issues. Assume that we're working with three interfaces: inside, outside, and DMZ. Let's say I have a server (X.Y.Z.1) that has to respond to PING, HTTP, SSH, FTP, MySQL, and SMTP. My ACL looks something like this: access-list outside_in extended permit icmp any host X.Y.Z.1 echo-reply access-list outside_in extended permit tcp any host X.Y.Z.1 eq www access-list outside_in extended permit tcp any host X.Y.Z.1 eq ssh access-list outside_in extended permit tcp any host X.Y.Z.1 eq ftp access-list outside_in extended permit tcp any host X.Y.Z.1 eq ftp-data established access-list outside_in extended permit tcp any host X.Y.Z.1 eq 3306 access-list outside_in extended permit tcp any host X.Y.Z.1 eq smtp and I apply it like this: access-group outside_in in interface outside My question is, what can I do for egress filtering? I want to only allow the minimal amount of traffic out. Do I just "reverse" the rules (i.e. the smtp rule becomes access-list inside_out extended permit tcp host X.Y.Z.1 any eq smtp ) and call it a day, or can I further cull my options? What can I safely block? Furthermore, when doing egress filtering, is it enough to apply "inverted" rules to the outside interface, or should I also look into making dmz_in and inside_in acls? I've heard the term "egress filtering" thrown around a lot, but I don't really know what I'm doing. Any pointers towards good resources and reading would also be helpful, most of the ones I've found presume that I know a lot more than I do.

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  • vmware player won't run on CentOS due to missing /dev/vmmon, what could be the problem?

    - by Graphics Noob
    So I've tried installing vmware player 3.1.4 and 3.1.3 and both times had the same problem, when I try to load a VM I get the error "Could not open /dev/vmmon". When I ls /dev/ I can see there is no "vmmon" device present. When I try running: sudo /etc/init.d/vmware start I get the output: Starting VMware services: VMware USB Arbitrator [ OK ] Virtual machine monitor [FAILED] Virtual machine communication interface [ OK ] VM communication interface socket family [ OK ] Blocking file system [ OK ] Virtual ethernet [FAILED] which shows that the Virtual Machine Monitor fails to load. I tried following the advice on this site and ran vmware-modconfig --console --install-all I notice during the compilation there are no errors, but at the end I get the message: Starting VMware services: VMware USB Arbitrator [ OK ] Virtual machine monitor [FAILED] Virtual machine communication interface [ OK ] VM communication interface socket family [ OK ] Blocking file system [ OK ] Virtual ethernet [ OK ] Unable to start services Out of curiousity I tried: sudo /sbin/insmod /lib/modules/2.6.18-238.9.1.el5xen/misc/vmmod.ko But got the error message: insmod: error inserting 'vmmon.ko': -1 Invalid module format I have a feeling this may be the root of the problem, but I don't know what could be causing it or how to fix it.

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  • What is the fall off of subsecond throughput on Ethernet Network Interfaces

    - by Kyle Brandt
    On a network interface, speeds are given in term of data over time, in particular, they are bits per second. However, in the uber-fast world of computing -- a second is kind of a really long time. So for example, given a linear falloff. A 1 GBit per second interface would do 500MBit per half second, 250Mbit per quarter second etc. I imagine at certain units of time, this is no longer linear. Perhaps this is set by ethernet frequencies, system clock speeds, interrupt timers etc. I am sure this varies depending on the system -- but does anyone have more information or whitepapers on this? One of the main reasons I am curious is to understand output drops on interfaces. Even if the speed per second is much lower than the interface can handle -- perhaps there are spikes that cause drops for only small numbers of milliseconds. Perhaps various coalescing would hide this effect -- or perhaps increase it on the receiving interface? Do queues make a difference here? Example: So given if this is linear down to the MS we would have 1Mbit/MS, and if Wireshark isn't distorting what I see, should I see drops when I have a spike beyond 1Mbit?

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  • ASA 5505 VPN setup. VPN works but still unable to reach devices in the inside network.

    - by chickenloop
    I've setup a Remote Access VPN on my Cisco ASA 5505. I'm able to connect to my ASA via my phone or the Cisco client, but I'm unable to reach devices in my inside LAN when connected via VPN. The setup is the following: Inside Network : 10.0.0.0/24 VPN_POOL: 172.16.0.0/24 Outside Network: 192.168.1.0/24 ASA is not the perimeter router, there is another device on the 192.168.1.0/24 network which is connected to my cable provider. Obviously UDP port 500 and 4500 are forwarded to the ASA's outside interface. Everything works perfectly, besides the VPN stuff. Config: interface Vlan1 nameif inside security-level 100 ip address 10.0.0.254 255.255.255.0 interface Vlan2 description Outside Interface nameif outside security-level 0 address 192.168.1.254 255.255.255.0 object network VPNPOOL subnet 172.16.0.0 255.255.255.0 object network INSIDE_LAN subnet 10.0.0.0 255.255.255.0 Then the exempt NAT rule. nat (inside,outside) source static INSIDE_LAN INSIDE_LAN destination static VPNPOOL VPNPOOL I don't think that the problem is with the VPN config, as I can successfully establish the VPN connection, but just in case I post it here: group-policy ZSOCA_ASA internal group-policy ZSOCA_ASA attributes vpn-tunnel-protocol ikev1 split-tunnel-policy tunnelspecified split-tunnel-network-list value Split-Tunnel default-domain value default.domain.invalid tunnel-group ZSOCA_ASA type remote-access tunnel-group ZSOCA_ASA general-attributes address-pool VPNPOOL default-group-policy ZSOCA_ASA tunnel-group ZSOCA_ASA ipsec-attributes ikev1 pre-shared-key ***** Any ideas are welcome. Regards.

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  • How to block access to addresses outside network (internet)

    - by devnull
    I have a homeserver, that is now connected to the internet with an own network device (ath0 - 192.168.1.x). It also has one more network interface (eth0 - 192.168.0.x). Soon I will get a second internet line that will be connected the second network. The server then has both networks with different internet lines available, but i only want it to connect to the internet on the old ath0 interface - not the new eth0 (192.168.0.x). Background of that constellation is that the new line has a volume-limit in traffic - the old hasn't and i need the new line for all mobile devices and laptops. The devices should be able to use the new network to connect to the internet and the server. The homeserver is a debian 6 with iptables and some already written rules for it. I need now a rule to block all outgoing internet access on the eth0 interface - i guess it could be something with --target != 192.168.0.0 but i did not succeed in finding the proper solution. Edit: found the solution: iptables -A OUTPUT -o eth0 -d 192.168.0.0/24 -m state --state NEW,ESTABLISHED -j ACCEPT With that setting, all traffic that uses the eth0 interface is only allowed if the destination is inside the network 192.168.0.x - all other traffic is denied .

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  • Ask How-To Geek: Learning the Office Ribbon, Booting to USB with an Old BIOS, and Snapping Windows

    - by Jason Fitzpatrick
    You’ve got questions and we’ve got answers. Today we highlight how to master the new Office interface, USB boot a computer with outdated BIOS, and snap windows to preset locations. Learning the New Office Ribbon Dear How-To Geek, I feel silly asking this (in light of how long the new Office interface has been out) but my company finally got around to upgrading from Windows XP and Office 2000 so the new interface it totally new to me. Can you recommend any resources for quickly learning the Office ribbon and the new changes? I feel completely lost after two decades of the old Office interface. Help! Sincerely, Where the Hell is Everything? Dear Where the Hell, We think most people were with you at some point in the last few years. “Where the hell is…” could possibly be the slogan for the new ribbon interface. You could browse through some of the dry tutorials online or even get a weighty book on the topic but the best way to learn something new is to get hands on. Ribbon Hero turns learning the new Office features and ribbon layout into a game. It’s no vigorous round of Team Fortress mind you, but it’s significantly more fun than reading a training document. Check out how to install and configure Ribbon Hero here. You’ll be teaching your coworkers new tricks in no time. Boot via USB with an Old BIOS Dear How-To Geek, I’m trying to repurpose some old computers by updating them with lightweight Linux distros but the BIOS on most of the machines is ancient and creaky. How ancient? It doesn’t even support booting from a USB device! I have a large flash drive that I’ve turned into a master installation tool for jobs like this but I can’t use it. The computers in question have USB ports; they just aren’t recognized during the boot process. What can I do? USB Bootin’ in Boise Dear USB Bootin’, It’s great you’re working to breathe life into old hardware! You’ve run into one of the limitations of older BIOSes, USB was around but nobody was thinking about booting off of it. Fortunately if you have a computer old enough to have that kind of BIOS it’s likely to also has a floppy drive or a CDROM drive. While you could make a bootable CDROM for your application we understand that you want to keep using the master USB installer you’ve made. In light of that we recommend PLoP Boot Manager. Think of it like a boot manager for your boot manager. Using it you can create a bootable floppy or CDROM that will enable USB booting of your master USB drive. Make a CD and a floppy version and you’ll have everything in your toolkit you need for future computer refurbishing projects. Read up on creating bootable media with PLoP Boot Manager here. Snapping Windows to Preset Coordinates Dear How-To Geek, Once upon a time I had a company laptop that came with a little utility that snapped windows to preset areas of the screen. This was long before the snap-to-side features in Windows 7. You could essentially configure your screen into a grid pattern of your choosing and then windows would neatly snap into those grids. I have no idea what it was called or if was anymore than a gimmick from the computer manufacturer, but I’d really like to have it on my new computer! Bend and Snap in San Francisco, Dear Bend and Snap, If we had to guess, we’d guess your company must have had a set of laptops from Acer as the program you’re describing sounds exactly like Acer GridVista. Fortunately for you the application was extremely popular and Acer released it independently of their hardware. If, by chance, you’ve since upgraded to a multiple monitor setup the app even supports multiple monitors—many of the configurations are handy for arranging IM windows and other auxiliary communication tools. Check out our guide to installing and configuring Acer GridVista here for more information. Have a question you want to put before the How-To Geek staff? Shoot us an email at [email protected] and then keep an eye out for a solution in the Ask How-To Geek column. Latest Features How-To Geek ETC How to Upgrade Windows 7 Easily (And Understand Whether You Should) The How-To Geek Guide to Audio Editing: Basic Noise Removal Install a Wii Game Loader for Easy Backups and Fast Load Times The Best of CES (Consumer Electronics Show) in 2011 The Worst of CES (Consumer Electronics Show) in 2011 HTG Projects: How to Create Your Own Custom Papercraft Toy Download the New Year in Japan Windows 7 Theme from Microsoft Once More Unto the Breach – Facebook Apps Can Now Access Your Address and Phone Number Dial Zero Speeds You Through Annoying Customer Service Menus Complete Dropquest 2011 and Receive Free Dropbox Storage Desktop Computer versus Laptop Wallpaper The Kids Have No Idea What Old Tech Is [Video]

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  • Computer Networks UNISA - Chap 12 &ndash; Networking Security

    - by MarkPearl
    After reading this section you should be able to Identify security risks in LANs and WANs and design security policies that minimize risks Explain how physical security contributes to network security Discuss hardware and design based security techniques Understand methods of encryption such as SSL and IPSec, that can secure data in storage and in transit Describe how popular authentication protocols such as RADIUS< TACACS,Kerberos, PAP, CHAP, and MS-CHAP function Use network operating system techniques to provide basic security Understand wireless security protocols such as WEP, WPA and 802.11i Security Audits Before spending time and money on network security, examine your networks security risks – rate and prioritize risks. Different organizations have different levels of network security requirements. Security Risks Not all security breaches result from a manipulation of network technology – there are human factors that can play a role as well. The following categories are areas of considerations… Risks associated with People Risks associated with Transmission and Hardware Risks associated with Protocols and Software Risks associated with Internet Access An effective security policy A security policy identifies your security goals, risks, levels of authority, designated security coordinator and team members, responsibilities for each team member, and responsibilities for each employee. In addition it specifies how to address security breaches. It should not state exactly which hardware, software, architecture, or protocols will be used to ensure security, nor how hardware or software will be installed and configured. A security policy must address an organizations specific risks. to understand your risks, you should conduct a security audit that identifies vulnerabilities and rates both the severity of each threat and its likelihood of occurring. Security Policy Content Security policy content should… Policies for each category of security Explain to users what they can and cannot do and how these measures protect the networks security Should define what confidential means to the organization Response Policy A security policy should provide for a planned response in the event of a security breach. The response policy should identify the members of a response team, all of whom should clearly understand the the security policy, risks, and measures in place. Some of the roles concerned could include… Dispatcher – the person on call who first notices the breach Manager – the person who coordinates the resources necessary to solve the problem Technical Support Specialist – the person who focuses on solving the problem Public relations specialist – the person who acts as the official spokesperson for the organization Physical Security An important element in network security is restricting physical access to its components. There are various techniques for this including locking doors, security people at access points etc. You should identify the following… Which rooms contain critical systems or data and must be secured Through what means might intruders gain access to these rooms How and to what extent are authorized personnel granted access to these rooms Are authentication methods such as ID cards easy to forge etc. Security in Network Design The optimal way to prevent external security breaches from affecting you LAN is not to connect your LAN to the outside world at all. The next best protection is to restrict access at every point where your LAN connects to the rest of the world. Router Access List – can be used to filter or decline access to a portion of a network for certain devices. Intrusion Detection and Prevention While denying someone access to a section of the network is good, it is better to be able to detect when an attempt has been made and notify security personnel. This can be done using IDS (intrusion detection system) software. One drawback of IDS software is it can detect false positives – i.e. an authorized person who has forgotten his password attempts to logon. Firewalls A firewall is a specialized device, or a computer installed with specialized software, that selectively filters or blocks traffic between networks. A firewall typically involves a combination of hardware and software and may reside between two interconnected private networks. The simplest form of a firewall is a packet filtering firewall, which is a router that examines the header of every packet of data it receives to determine whether that type of packet is authorized to continue to its destination or not. Firewalls can block traffic in and out of a LAN. NOS (Network Operating System) Security Regardless of the operating system, generally every network administrator can implement basic security by restricting what users are authorized to do on a network. Some of the restrictions include things related to Logons – place, time of day, total time logged in, etc Passwords – length, characters used, etc Encryption Encryption is the use of an algorithm to scramble data into a format that can be read only by reversing the algorithm. The purpose of encryption is to keep information private. Many forms of encryption exist and new ways of cracking encryption are continually being invented. The following are some categories of encryption… Key Encryption PGP (Pretty Good Privacy) SSL (Secure Sockets Layer) SSH (Secure Shell) SCP (Secure CoPy) SFTP (Secure File Transfer Protocol) IPSec (Internet Protocol Security) For a detailed explanation on each section refer to pages 596 to 604 of textbook Authentication Protocols Authentication protocols are the rules that computers follow to accomplish authentication. Several types exist and the following are some of the common authentication protocols… RADIUS and TACACS PAP (Password Authentication Protocol) CHAP and MS-CHAP EAP (Extensible Authentication Protocol) 802.1x (EAPoL) Kerberos Wireless Network Security Wireless transmissions are particularly susceptible to eavesdropping. The following are two wireless network security protocols WEP WPA

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  • C# 4.0: Covariance And Contravariance In Generics

    - by Paulo Morgado
    C# 4.0 (and .NET 4.0) introduced covariance and contravariance to generic interfaces and delegates. But what is this variance thing? According to Wikipedia, in multilinear algebra and tensor analysis, covariance and contravariance describe how the quantitative description of certain geometrical or physical entities changes when passing from one coordinate system to another.(*) But what does this have to do with C# or .NET? In type theory, a the type T is greater (>) than type S if S is a subtype (derives from) T, which means that there is a quantitative description for types in a type hierarchy. So, how does covariance and contravariance apply to C# (and .NET) generic types? In C# (and .NET), variance applies to generic type parameters and not to the resulting generic type. A generic type parameter is: covariant if the ordering of the generic types follows the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. contravariant if the ordering of the generic types is reversed from the ordering of the generic type parameters: Generic<T> = Generic<S> for T = S. invariant if neither of the above apply. If this definition is applied to arrays, we can see that arrays have always been covariant because this is valid code: object[] objectArray = new string[] { "string 1", "string 2" }; objectArray[0] = "string 3"; objectArray[1] = new object(); However, when we try to run this code, the second assignment will throw an ArrayTypeMismatchException. Although the compiler was fooled into thinking this was valid code because an object is being assigned to an element of an array of object, at run time, there is always a type check to guarantee that the runtime type of the definition of the elements of the array is greater or equal to the instance being assigned to the element. In the above example, because the runtime type of the array is array of string, the first assignment of array elements is valid because string = string and the second is invalid because string = object. This leads to the conclusion that, although arrays have always been covariant, they are not safely covariant – code that compiles is not guaranteed to run without errors. In C#, the way to define that a generic type parameter as covariant is using the out generic modifier: public interface IEnumerable<out T> { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> { T Current { get; } bool MoveNext(); } Notice the convenient use the pre-existing out keyword. Besides the benefit of not having to remember a new hypothetic covariant keyword, out is easier to remember because it defines that the generic type parameter can only appear in output positions — read-only properties and method return values. In a similar way, the way to define a type parameter as contravariant is using the in generic modifier: public interface IComparer<in T> { int Compare(T x, T y); } Once again, the use of the pre-existing in keyword makes it easier to remember that the generic type parameter can only be used in input positions — write-only properties and method non ref and non out parameters. Because covariance and contravariance apply only to the generic type parameters, a generic type definition can have both covariant and contravariant generic type parameters in its definition: public delegate TResult Func<in T, out TResult>(T arg); A generic type parameter that is not marked covariant (out) or contravariant (in) is invariant. All the types in the .NET Framework where variance could be applied to its generic type parameters have been modified to take advantage of this new feature. In summary, the rules for variance in C# (and .NET) are: Variance in type parameters are restricted to generic interface and generic delegate types. A generic interface or generic delegate type can have both covariant and contravariant type parameters. Variance applies only to reference types; if you specify a value type for a variant type parameter, that type parameter is invariant for the resulting constructed type. Variance does not apply to delegate combination. That is, given two delegates of types Action<Derived> and Action<Base>, you cannot combine the second delegate with the first although the result would be type safe. Variance allows the second delegate to be assigned to a variable of type Action<Derived>, but delegates can combine only if their types match exactly. If you want to learn more about variance in C# (and .NET), you can always read: Covariance and Contravariance in Generics — MSDN Library Exact rules for variance validity — Eric Lippert Events get a little overhaul in C# 4, Afterward: Effective Events — Chris Burrows Note: Because variance is a feature of .NET 4.0 and not only of C# 4.0, all this also applies to Visual Basic 10.

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  • Oracle’s Web Experience Management

    - by Christie Flanagan
    Today’s guest post on Oracle’s Web Experience Management comes from a member of our WebCenter Evangelist team, Noël Jaffré, a Principal Technologist based in France.Oracle’s Web Experience Management (WEM) solution enables organizations to optimize the online channel for driving marketing and customer experience management success. It empowers business users to manage the web presence and create rich and engaging online experiences for customers and prospects. Oracle's WEM platform provides a framework to simplify the integration of Oracle, third-party and custom-built applications. This framework essentially allows the creation and integration of applications using one single business interface called the WEM interface. It includes the following: Single sign-on access control for all integrated applications using the Central Authentication Service (CAS) component. A single centralized administration window for user, role, and native applications management including site management. Community server management, gadget server management as well as management for partner integrated technologies. A Representational State Transfer (REST) API for accessing WebCenter Sites data. REST services are supported on both Oracle WebCenter Sites and Oracle WebCenter Sites Satellite Server to leverage the satellite server cache. All REST requests are cached for web consuming applications as well for the high performance delivery of native applications on the mobile channel. Oracle WebCenter Sites’ Web Experience Management environment enables organizations to deliver a compelling online experience to customers by simplifying the deployment and management of sophisticated and engaging websites. The WebCenter Sites platform automates the entire process of managing web content including: Authoring:  Business users can easily contribute and manage web content in real-time, with intuitive interfaces and drag-and-drop content authoring and layout capabilities designed for the non-technical user. Contextual Content Targeting: Marketers are empowered to create and manage targeted campaigns with relevant recommendations and promotions based on the context of the session of the visitor such as his or her navigation history, user profile, language, location or other information shared during the visitor session. Content Publishing and Deployment: It offers advanced multi-site management capabilities for departmental or regional sites, as well as strong multi-lingual and multi-locale content management. The remote satellite server caching infrastructure provides high-performance, distributed caching, tuned to deliver high-volume, targeted and multi-lingual sites. Analytics and Optimization: Business users and marketers have the ability to measure the effectiveness of their online content and campaigns at a granular level. Editors and marketers can immediately determine whether a given article or promotion is relevant to a particular customer segment. User-generated Content: Marketers can enable blogs, comments, rating and reviews on the website.  All comments and reviews posted to the website can be moderated from the administrator interface either manually or automatically using filters, whitelists, blacklists or community based moderation. Personalized Gadget Dashboards:  Site managers can deploy gadgets, small applications using web content, individually or as part of dashboards containing multiple gadgets.  These gadget dashboards enable site visitors to create their own “MyPage” on a given site where they can select and customize the gadgets that the site administrator has made available.  Any gadget that conforms to the iGoogle/OpenSocial standard can be made available to site visitors, or they can be created within the WEM interface. Oracle's WEM platform also provides a unique environment for the delivery of a rich, multichannel online experience for site visitors through its advanced management modules for mobile. With Oracle’s WEM solution, it’s easy to control branding and deliver a consistent message while repurposing web content for publication to mobile devices, kiosks and much more. This distinctive approach provides: HTML5 Delivery: HTML5 delivery which includes native support for adaptive design that responds to the user’s computer screen resolution and orientation. The approach is less driven by the particular hardware and more driven by the user’s interactions with the device. In other words, this approach takes both the screen interactions (either cursor or touch) and screen sizes and orientation into consideration. A Unique Native Mobile Extension Environment for Contributors: From the WEM interface, a contributor can directly manage their mobile channel, using the tooling already in place for driving the traditional web presence. This includes the mobile presentation, as well as mobile insite editing, drag and drop page layout, and in-context recommendations and personalization. Optimized REST APIs for High Performance Content Delivery on Native Mobile Device Applications: WebCenter Sites’ REST API uses the underlying HTTP methods (GET, POST, PUT, DELETE) to interact with resources. Resources support two types of input and output formats -- XML and JSON. REST calls are customizable to optimize the interactions between the content repositories and the client applications. Caching is essential to decrease network loads and improve overall reliability and usability of the applications and user interactions. REST results are cached through the highly efficient Oracle WebCenter Sites caching architecture.

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  • Bring Office 2003 Menus Back to 2010 with UBitMenu

    - by Matthew Guay
    Are you having trouble getting used to the Ribbon interface in Office 2010?  Here’s how you can roll back the clock a bit and bring back the familiar menus and toolbars from 2003. The Office 2007 Ribbon was both praised and criticized.  While many users felt they were more productive with the new interface, others felt frustrated searching for commands they had memorized in older versions of Office.  Now, with Office 2010, the ribbon interface has been brought to every app in the Office suite, and is integrated into many newer programs from Microsoft. If you’re moving from Office 2003, using UBitMenu allows you to add the old familiar menus back along with the new Ribbon interface for an easier learning curve. Also, with the customizability of Office 2010, we can strip away the extra Ribbon tabs to make it more like 2003. Get the 2003 Menus and Toolbars Back in Office 2010 Download UBitMenu (link below), and install as normal.  Make sure all of your Office programs are closed during the installation.  This handy utility is very small, and installed amazingly quick. Open Word, Excel, or PowerPoint and there’s now a new Menu tab beside Home in the Ribbon.  Now you can access all of your favorite old Office commands in the familiar menus, and access many of the newer Office features such as SmartArt.   Here’s a close-up of the toolbar.  Notice that the layout is very similar to that of Word 2003. You can access all of the new Transitions in PowerPoint 2010 from the menu bar.   The menu in Excel even included support for the new PivotTable and PivotCharts Wizard. One problem we noticed was that the toolbars were condensed to a drop-down menu if the Office window was less than 870px wide.  This may be a frustration to users with low-resolution displays, and you might want to use the Office Apps maximized. Get Rid of the Ribbon Now that you’ve got the old menus back, you can get rid of the extra ribbon tabs if you’d like.  Office 2010 lets you customize your ribbon and remove tabs, so let’s get rid of all the other tabs except for our new Menu tab.  In our example we’re using Word, but you can do it in Excel or PowerPoint the same way. Click the File tab and select Options. Alternately, in the Menu tab, select Tools and then Word Options. Select Customize Ribbon on the left sidebar, then uncheck the boxes beside all the ribbon tabs you want to hide on the right.  Click Ok when you’re finished. While you’re at it, you can change the default color scheme as well. Note: The color change will automatically change the color scheme in all of the Office apps, so you’ll only need to do that once. Now the ribbon only has 2 tabs…the File tab for the new Backstage View, and the UBitMenu tab we just installed.  It almost has the appearance Word 2003, but with the new features of Word 2010!  You’ll need to repeat these steps in Excel and PowerPoint if you want to customize their ribbon the same.   Conclusion If you’ve been having a hard time getting used to Office 2010, UBitMenu is a great way to get familiar with the new interface, or simply stay productive with your old tricks.  We do wish it supported the other Office applications like OneNote and Outlook. That doesn’t make it a deal breaker though, it can make the learning curve easier in Word, PowerPoint, and Excel. UBitMenu is free for personal use, and available at a very reasonable price for businesses. If you’re using Office 2007 and not a fan of the Ribbon, UBitMenu works for it as well. Download UBitMenu Similar Articles Productive Geek Tips How To Bring Back the Old Menus in Office 2007Upgrade Office 2003 to 2010 on XP or Run them Side by SideHow to Find Office 2003 Commands in Office 2010Make Word 2007 Always Save in Word 2003 FormatMake Excel 2007 Always Save in Excel 2003 Format TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips HippoRemote Pro 2.2 Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Speed Up Windows With ReadyBoost Awesome World Cup Soccer Calendar Nice Websites To Watch TV Shows Online 24 Million Sites Windows Media Player Glass Icons (icons we like) How to Forecast Weather, without Gadgets

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  • Computer Networks UNISA - Chap 15 &ndash; Network Management

    - by MarkPearl
    After reading this section you should be able to Understand network management and the importance of documentation, baseline measurements, policies, and regulations to assess and maintain a network’s health. Manage a network’s performance using SNMP-based network management software, system and event logs, and traffic-shaping techniques Identify the reasons for and elements of an asset managements system Plan and follow regular hardware and software maintenance routines Fundamentals of Network Management Network management refers to the assessment, monitoring, and maintenance of all aspects of a network including checking for hardware faults, ensuring high QoS, maintaining records of network assets, etc. Scope of network management differs depending on the size and requirements of the network. All sub topics of network management share the goals of enhancing the efficiency and performance while preventing costly downtime or loss. Documentation The way documentation is stored may vary, but to adequately manage a network one should at least record the following… Physical topology (types of LAN and WAN topologies – ring, star, hybrid) Access method (does it use Ethernet 802.3, token ring, etc.) Protocols Devices (Switches, routers, etc) Operating Systems Applications Configurations (What version of operating system and config files for serve / client software) Baseline Measurements A baseline is a report of the network’s current state of operation. Baseline measurements might include the utilization rate for your network backbone, number of users logged on per day, etc. Baseline measurements allow you to compare future performance increases or decreases caused by network changes or events with past network performance. Obtaining baseline measurements is the only way to know for certain whether a pattern of usage has changed, or whether a network upgrade has made a difference. There are various tools available for measuring baseline performance on a network. Policies, Procedures, and Regulations Following rules helps limit chaos, confusion, and possibly downtime. The following policies and procedures and regulations make for sound network management. Media installations and management (includes designing physical layout of cable, etc.) Network addressing policies (includes choosing and applying a an addressing scheme) Resource sharing and naming conventions (includes rules for logon ID’s) Security related policies Troubleshooting procedures Backup and disaster recovery procedures In addition to internal policies, a network manager must consider external regulatory rules. Fault and Performance Management After documenting every aspect of your network and following policies and best practices, you are ready to asses you networks status on an on going basis. This process includes both performance management and fault management. Network Management Software To accomplish both fault and performance management, organizations often use enterprise-wide network management software. There various software packages that do this, each collect data from multiple networked devices at regular intervals, in a process called polling. Each managed device runs a network management agent. So as not to affect the performance of a device while collecting information, agents do not demand significant processing resources. The definition of a managed devices and their data are collected in a MIB (Management Information Base). Agents communicate information about managed devices via any of several application layer protocols. On modern networks most agents use SNMP which is part of the TCP/IP suite and typically runs over UDP on port 161. Because of the flexibility and sophisticated network management applications are a challenge to configure and fine-tune. One needs to be careful to only collect relevant information and not cause performance issues (i.e. pinging a device every 5 seconds can be a problem with thousands of devices). MRTG (Multi Router Traffic Grapher) is a simple command line utility that uses SNMP to poll devices and collects data in a log file. MRTG can be used with Windows, UNIX and Linux. System and Event Logs Virtually every condition recognized by an operating system can be recorded. This is typically done using event logs. In Windows there is a GUI event log viewer. Similar information is recorded in UNIX and Linux in a system log. Much of the information collected in event logs and syslog files does not point to a problem, even if it is marked with a warning so it is important to filter your logs appropriately to reduce the noise. Traffic Shaping When a network must handle high volumes of network traffic, users benefit from performance management technique called traffic shaping. Traffic shaping involves manipulating certain characteristics of packets, data streams, or connections to manage the type and amount of traffic traversing a network or interface at any moment. Its goals are to assure timely delivery of the most important traffic while offering the best possible performance for all users. Several types of traffic prioritization exist including prioritizing traffic according to any of the following characteristics… Protocol IP address User group DiffServr VLAN tag in a Data Link layer frame Service or application Caching In addition to traffic shaping, a network or host might use caching to improve performance. Caching is the local storage of frequently needed files that would otherwise be obtained from an external source. By keeping files close to the requester, caching allows the user to access those files quickly. The most common type of caching is Web caching, in which Web pages are stored locally. To an ISP, caching is much more than just convenience. It prevents a significant volume of WAN traffic, thus improving performance and saving money. Asset Management Another key component in managing networks is identifying and tracking its hardware. This is called asset management. The first step to asset management is to take an inventory of each node on the network. You will also want to keep records of every piece of software purchased by your organization. Asset management simplifies maintaining and upgrading the network chiefly because you know what the system includes. In addition, asset management provides network administrators with information about the costs and benefits of certain types of hardware or software. Change Management Networks are always in a stage of flux with various aspects including… Software changes and patches Client Upgrades Shared Application Upgrades NOS Upgrades Hardware and Physical Plant Changes Cabling Upgrades Backbone Upgrades For a detailed explanation on each of these read the textbook (Page 750 – 761)

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