Cannot ping host stale ARP cache?
- by gkchicago
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