You're probably going to just tell me to upgrade but...
Anyone seen this?
We have a RedHat 6.2 system with stock kernel with two Intel
Etherexpress Pro 10/100 cards:
alias eth0 eepro100
alias eth1 eepro100
"eth0" has the IP and MAC address of:
172.16.128.79 00:B0:D0:21:A3:7F
and "eth1":
172.16.130.79 00:D0:B7:44:2D:41
Note the mask is 255.255.254.0 so they're on different subnets.
The weird thing we're getting is that sometimes somehow our Cisco which
is connected to both subnets is learning both IP addresses against the
MAC of "eth0", eg (from "show arp"):
Internet 172.16.128.79 1 00b0.d021.a37f ARPA FastEthernet3/1
Internet 172.16.130.79 190 00b0.d021.a37f ARPA FastEthernet3/0
^^^^^^^^^^^^^^
||||||||||||||
Wrong! Should be: 00d0.b744.2d41!
meaning packets that should be bound out "eth1" must somehow be leaking
out "eth0" and causing the Cisco ARP table to get maligned. Since most
hosts off-net of either of these nets use the same Cisco to route to
this host (and the host is multihomed in the DNS), the Cisco when
forwarding the routed packets wrongly thinks it knows the correct arp
for the 172.16.130.79 (eth1) address and then doesn't try to arp up the
address. This in turn causes it to forward the packets against the wrong
MAC which are then ignored since they don't show up against the correct
interface/MAC combination.
The only guess I have is something to do with interface naming confusion
(which I vaguely remember reading about somewhere) or a kernel bug.
Any guesses, advice, etc?
Thanks,
- Matt
--
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Matt Fahrner 2 South Park St.
Manager of Networking Willis House
Burlington Coat Factory Warehouse Lebanon, N.H. 03766
TEL: (603) 448-4100 xt 5150 USA
FAX: (603) 443-6190 [EMAIL PROTECTED]
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