I have a server that has some VMs, but the VMs can't communicate properly with the server because the server has several interfaces, and it responds on the wrong one.

Q: We know that there is a kernel parameter that can ensure that ARP responses will come only from that interface where the request went. What is that sysctl setting?

Server is Debian machine.


1 Answer 1


You need to execute:

sysctl -w net.ipv4.conf.all.arp_filter=1

This can be useful reading: Multiple network interfaces and ARP flux

  • this will be only permament if I edit "/etc/sysctl.conf"? Feb 7, 2012 at 14:59
  • from kernel.org/doc/Documentation/networking/ip-sysctl.txt : arp_filter - BOOLEAN / 1 - Allows you to have multiple network interfaces on the same subnet, In other words it allows control of which cards (usually 1) will respond to an arp request. / 0 - (default) The kernel can respond to arp requests with addresses from other interfaces. This may seem wrong but it usually makes sense, because it increases the chance of successful communication. Jun 5, 2017 at 20:17

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