Messages in this thread | | | Date | Wed, 2 Nov 2011 18:31:19 -0400 | Subject | Question about new ARP reply behaviour since 2.6.31 | From | Fred Qiu <> |
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Hello,
I recently found out that the kernel since version 2.6.31 does not send ARP reply out on interface which is not the first routing destination. This behaviour breaks things in my setup which relies on the old behaviour. The kernel before 2.6.31 sends out ARP replies out on the interface from which the ARP request has been received regardless the routing table.
For example, I have a box with two interfaces, eth0 & eth1, which connect to two different networks. The two interfaces are configured with overlapping subnets, i.e. 192.168.0.1/24 and 192.168.0.2/24. The first routing entry for network 192.168.0.0/24 is on eth0. Now the ARP requests for 192.168.0.2 received by eth1 from the second network are never being answered.
Could someone please point me to any document regarding this change? Why is this change needed in the first place? Also any suggestion on forcing the kernel to reply the ARP request on secondary interface would be very helpful.
Thanks!
Fred
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