Networking issues with Linux server (CentOS 5.3)

Posted by sxanness on Server Fault See other posts from Server Fault or by sxanness
Published on 2009-11-09T17:03:37Z Indexed on 2010/03/08 0:32 UTC
Read the original article Hit count: 629

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I have a Linux server hosting our bug tracking software (CentOS 5.2 Kernel 2.6.18-128.4.1.el5) that I have having some strange network problems with. The machine is configured with two NICS, one for the public interface and the other for our server back end network.

The problem is that after doing a service network restart I can ping the public interface and it sends anywhere from 200-500 ICMP packets and then all of a sudden I start getting a request timed out error. Strange but as soon as I connect to the private interface the ping starts working again to the public interface. I clearly have a routing issue somewhere.

I have a Juniper Router with the following configuration.

Interface 0/0 -- Connect subnet to the ISP at our co-location Interface 0/2 -- For our DRAC network Interface 0/3 -- The Server-backend network (plugs directly into a switch that feeds to all the NICs that are on the 10.3.20.x network. Interface 0/4 -- Plugs directly into another switch that feeds our public interfaces, that interface as all the gateways from our public ip rangs as secondary IP addresses.

I hope that someone can ask the right questions that can lead me to check things and figure out what is going on. Has anyone had similar problems and what kind of things should I be checking? Routing issue or something even more complicated?

[[email protected] ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+
DEVICE=eth0
BOOTPROTO=static
IPADDR=72.249.134.98
NETMASK=255.255.255.248
BROADCAST=72.249.134.103
HWADDR=00:16:3E:AA:BB:EE
ONBOOT=yes
[[email protected] ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+
DEVICE=eth1
BOOTPROTO=static
BROADCAST=10.3.20.255
HWADDR=00:17:3E:AA:BB:EE
IPADDR=10.3.20.25
NETMASK=255.255.255.0
NETWORK=10.3.20.0
ONBOOT=yes

[[email protected] ~]# cat /etc/sysconfig/network
NETWORKING=yes
NETWORKING_IPV6=no
HOSTNAME=fogbugz.dfw.hisg-it.net
GATEWAY=72.249.134.97

[[email protected] ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
72.249.134.96   0.0.0.0         255.255.255.248 U     0      0        0 eth0
10.3.20.0       0.0.0.0         255.255.255.0   U     0      0        0 eth1
169.254.0.0     0.0.0.0         255.255.0.0     U     0      0        0 eth1
10.0.0.0        10.3.20.1       255.0.0.0       UG    0      0        0 eth1
0.0.0.0         72.249.134.97   0.0.0.0         UG    0      0        0 eth0

© Server Fault or respective owner

Networking issues with Linux server (CentOS 5.3)

Posted by sxanness on Server Fault See other posts from Server Fault or by sxanness
Published on 2009-11-09T17:03:37Z Indexed on 2010/03/08 3:32 UTC
Read the original article Hit count: 629

Filed under:
|
|
|

I have a Linux server hosting our bug tracking software (CentOS 5.2 Kernel 2.6.18-128.4.1.el5) that I have having some strange network problems with. The machine is configured with two NICS, one for the public interface and the other for our server back end network.

The problem is that after doing a service network restart I can ping the public interface and it sends anywhere from 200-500 ICMP packets and then all of a sudden I start getting a request timed out error. Strange but as soon as I connect to the private interface the ping starts working again to the public interface. I clearly have a routing issue somewhere.

I have a Juniper Router with the following configuration.

Interface 0/0 -- Connect subnet to the ISP at our co-location Interface 0/2 -- For our DRAC network Interface 0/3 -- The Server-backend network (plugs directly into a switch that feeds to all the NICs that are on the 10.3.20.x network. Interface 0/4 -- Plugs directly into another switch that feeds our public interfaces, that interface as all the gateways from our public ip rangs as secondary IP addresses.

I hope that someone can ask the right questions that can lead me to check things and figure out what is going on. Has anyone had similar problems and what kind of things should I be checking? Routing issue or something even more complicated?

[[email protected] ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
# Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+
DEVICE=eth0
BOOTPROTO=static
IPADDR=72.249.134.98
NETMASK=255.255.255.248
BROADCAST=72.249.134.103
HWADDR=00:16:3E:AA:BB:EE
ONBOOT=yes
[[email protected] ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth1
# Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+
DEVICE=eth1
BOOTPROTO=static
BROADCAST=10.3.20.255
HWADDR=00:17:3E:AA:BB:EE
IPADDR=10.3.20.25
NETMASK=255.255.255.0
NETWORK=10.3.20.0
ONBOOT=yes

[[email protected] ~]# cat /etc/sysconfig/network
NETWORKING=yes
NETWORKING_IPV6=no
HOSTNAME=fogbugz.dfw.hisg-it.net
GATEWAY=72.249.134.97

[[email protected] ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
72.249.134.96   0.0.0.0         255.255.255.248 U     0      0        0 eth0
10.3.20.0       0.0.0.0         255.255.255.0   U     0      0        0 eth1
169.254.0.0     0.0.0.0         255.255.0.0     U     0      0        0 eth1
10.0.0.0        10.3.20.1       255.0.0.0       UG    0      0        0 eth1
0.0.0.0         72.249.134.97   0.0.0.0         UG    0      0        0 eth0

© Server Fault or respective owner

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