I am having a strange issue with a Debian (Lenny/Linux 2.6.26-2-amd64) that has been driving me nuts. On some machines within my network I can ping the host in question just fine, other times I have to manually hard-code the ARP ethernet address for the IP in order to establish connectivity. I've finally worked it down to somehow involving ARP. I just found how to fix it in a way that made it work but I'm looking for help explaining this issue and also I don't trust my fix to be permanent..

My thought process has been the following but I just can't make any sense out of it:

• Could it be the card? (Intel 82555 rev 4)
• Could it be because there are two network cards? (Default route is eth0)
• Could it be because of the network aliases?
• Lenny?
• AMD x86_64?
• Argh..

Thank you for any insight you might have

// Ping doesn't go thru
[gordon@ubuntu ~]$ ping 192.168.135.101
PING 192.168.135.101 (192.168.135.101) 56(84) bytes of data.

--- 192.168.135.101 ping statistics ---
4 packets transmitted, 0 received, 100% packet loss, time 3014ms

// Here's the ARP Table, sometimes the .151 address is good, sometimes it
// also matches the Gateways MAC like .101 is doing right here.
[gordon@ubuntu ~]$ cat /proc/net/arp
IP address       HW type     Flags       HW address            Mask     Device
192.168.135.15   0x1         0x2         00:0B:DB:2B:24:89     *        eth0
192.168.135.151  0x1         0x2         00:0B:6A:3A:30:A6     *        eth0
192.168.135.1    0x1         0x2         00:1A:A2:2D:2A:04     *        eth0
192.168.135.101  0x1         0x2         00:1A:A2:2D:2A:04     *        eth0

// Drop the bad arp table listing and set it manually based on /sbin/ifconfig
[gordon@ubuntu ~]$ sudo arp -d 192.168.135.101
[gordon@ubuntu ~]$ sudo arp -s 192.168.135.101 00:0B:6A:3A:30:A6

// Ping starts going thru..?!?
[gordon@ubuntu ~]$ ping 192.168.135.101
PING 192.168.135.101 (192.168.135.101) 56(84) bytes of data.
64 bytes from 192.168.135.101: icmp_seq=1 ttl=64 time=15.8 ms
64 bytes from 192.168.135.101: icmp_seq=2 ttl=64 time=15.9 ms
64 bytes from 192.168.135.101: icmp_seq=3 ttl=64 time=16.0 ms
64 bytes from 192.168.135.101: icmp_seq=4 ttl=64 time=15.9 ms

--- 192.168.135.101 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3012ms
rtt min/avg/max/mdev = 15.836/15.943/16.064/0.121 ms

The following is my network config on this.

gordon@db01:~$ /sbin/ifconfig
eth0      Link encap:Ethernet  HWaddr 00:0b:6a:3a:30:a6
          inet addr:192.168.135.151  Bcast:192.168.135.255  Mask:255.255.255.0
          inet6 addr: fe80::20b:6aff:fe3a:30a6/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:15476725 errors:0 dropped:0 overruns:0 frame:0
          TX packets:10030036 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:18565307359 (17.2 GiB)  TX bytes:3412098075 (3.1 GiB)

eth0:0    Link encap:Ethernet  HWaddr 00:0b:6a:3a:30:a6
          inet addr:192.168.135.150  Bcast:192.168.135.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

eth0:1    Link encap:Ethernet  HWaddr 00:0b:6a:3a:30:a6
          inet addr:192.168.135.101  Bcast:192.168.135.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

eth1      Link encap:Ethernet  HWaddr 00:e0:81:2a:6e:d0
          inet addr:10.10.62.1  Bcast:10.10.62.255  Mask:255.255.255.0
          inet6 addr: fe80::2e0:81ff:fe2a:6ed0/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:10233315 errors:0 dropped:0 overruns:0 frame:0
          TX packets:19400286 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1112500658 (1.0 GiB)  TX bytes:27952809020 (26.0 GiB)
          Interrupt:24

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:387 errors:0 dropped:0 overruns:0 frame:0
          TX packets:387 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:41314 (40.3 KiB)  TX bytes:41314 (40.3 KiB)

gordon@db01:~$ sudo mii-tool -v eth0
eth0: negotiated 100baseTx-FD, link ok
  product info: Intel 82555 rev 4
  basic mode:   autonegotiation enabled
  basic status: autonegotiation complete, link ok
  capabilities: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD
  advertising:  100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control
  link partner: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD

gordon@db01:~$ sudo route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
localnet        *               255.255.255.0   U     0      0        0 eth0
10.10.62.0      *               255.255.255.0   U     0      0        0 eth1
default         192.168.135.1   0.0.0.0         UG    0      0        0 eth0