Please bear with me as I know I have included a lot of detail.
Description
Redhat AS 3
Kernel 2.4.21-47.0.1.ELsmp
eth0 HWaddr 00:07:E9:11:30:76
inet addr:192.168.1.3 Bcast:192.168.1.255 Mask:255.255.255.0
eth0:1 HWaddr 00:07:E9:11:30:76
inet addr:192.168.3.1 Bcast:192.168.3.255 Mask:255.255.255.0
This interface is up but with no IP address
eth1 HWaddr 00:07:E9:11:30:77
eth1.101 10.10.1.1 Bcast:10.10.1.255 Mask:255.255.255.0 vlan 101
eth1.102 10.10.2.1 Bcast:10.10.2.255 Mask:255.255.255.0 vlan 102
eth1.103 10.10.3.1 Bcast:10.10.3.255 Mask:255.255.255.0 vlan 103
eth1.104 10.10.4.1 Bcast:10.10.4.255 Mask:255.255.255.0 vlan 104
eth1.105 10.10.5.1 Bcast:10.10.5.255 Mask:255.255.255.0 vlan 105
eth1.106 10.10.6.1 Bcast:10.10.6.255 Mask:255.255.255.0 vlan 106
eth1.107 10.10.7.1 Bcast:10.10.7.255 Mask:255.255.255.0 vlan 107
eth1.108 10.10.8.1 Bcast:10.10.8.255 Mask:255.255.255.0 vlan 108
eth1.109 10.10.9.1 Bcast:10.10.9.255 Mask:255.255.255.0 vlan 109
eth2 Link encap:Ethernet HWaddr 00:06:5B:FE:56:C2
BROADCAST MULTICAST MTU:1500 Metric:1
eth3 Link encap:Ethernet HWaddr 00:06:5B:FE:56:C3
BROADCAST MULTICAST MTU:1500 Metric:1
This machine is routing between the vlans. When I ping 10.10.5.105 I
get Host Unreachable. Here is tcpdump from the ping on the router.
tcpdump -i eth1.105
14:10:28.254008 arp who-has 10.10.5.105 tell 10.10.5.1
14:10:29.250067 arp who-has 10.10.5.105 tell 10.10.5.1
14:10:30.250143 arp who-has 10.10.5.105 tell 10.10.5.1
Ok now I go to the device via a serial port and ping back to 10.10.5.1 (
the router ) and here is the tcpdump output
tcpdump -i eth1.105 -n
tcpdump: listening on eth1.105
14:12:06.706722 arp who-has 10.10.5.1 tell 10.10.5.105
14:12:06.706798 arp reply 10.10.5.1 is-at 0:7:e9:11:30:77
14:12:06.707715 10.10.5.105 > 10.10.5.1: icmp: echo request (DF)
14:12:06.707762 10.10.5.1 > 10.10.5.105: icmp: echo reply
14:12:07.723100 10.10.5.105 > 10.10.5.1: icmp: echo request (DF)
14:12:07.723136 10.10.5.1 > 10.10.5.105: icmp: echo reply
Now of course I can ping 10.10.5.10 (the suspect device) from 10.10.5.1
( the router )
ping 10.10.5.1
PING 10.10.5.1 (10.10.5.1) 56(84) bytes of data.
64 bytes from 10.10.5.1: icmp_seq=0 ttl=64 time=0.068 ms
64 bytes from 10.10.5.1: icmp_seq=1 ttl=64 time=0.039 ms
This is fine untill the arp entry ages out. Then I back to not being
able to ping the device.
If I manually insert an arp table entry all is well. No filtering in
the switches. Switches are SMC 6826 for the 10/100 and 8724 for the
core and gig e.
I have several similar symptoms like this in various places. I have
some devices on vlans that I see the dhcp discover messages and I see
the dhcp offer then the device sends another dhcp discover. This goes
on for a few times and the device just waits and starts the process over.
I feel that the problem lies in the handling of arp requests but I guess
I just don't know enough about how linux handles them or how to control
them to find a solution.
Any ideas ?
Alan
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