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How to avoid ARP flux issue in linux?

+2 votes
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I have a setup where eth0 and eth1 interfaces are in same broadcast domain.

But i have a virtual IP configured on eth1 and a physical ip on eth0.
It is observed that if eth0 is default route then eth0 will respond to arp request for the IP configured on eth1.

This would cause an issue since traffic will be routed via eth0.

posted Apr 17, 2013 by Prem Chaitanya Prathi

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Try the following too -

net.ipv4.conf.all.arp_ignore=1
net.ipv4.conf.all.arp_announce=2

Setting net.ipv4.conf.all.arp_ignore=1 and net.ipv4.conf.all.arp_announce=2 in /etc/sysctl.conf provides adequate settings. However, you should check whether these settings work in your network environment, especially if you depend on reaching an IP address from any other than the interface that it is configured on.

1 Answer

+1 vote

Try to disable rp_filter on each interface and try

# sysctl -w net.ipv4.conf.eth0.rp_filter=0
# sysctl -w net.ipv4.conf.eth1.rp_filter=0

Hope it should work.

answer Apr 17, 2013 by anonymous
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Lets assume device is a computer which is connected to LAN switch and LAN switch has further links in upward.
Does a computer initiate ARP request for each destination IP ? Or it initiates ARP request only for a specific group of IPs ?

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