Currently, I have a set up where a machine has multiple IP addresses. For some experimentation, I have set up some ip rule entries such that for certain IP addresses, the packet gets forwarded to another virtual interface that is local on the device.

The issue is now, for this specific IP address, when it receives an ARP request for this IP address, it seems like the machine doesn't identify it as a local IP address anymore.

Is there a way to either force an ARP reply for these addresses (which point to a local virtual interface)?

I am running on Ubuntu 16.04. For example, for one of the IP Address, let's call it <x>, I added an IP rule in a table that overrides the local routing table. ip route add <x> dev <internal-virtual-interface>

So if I did ip route get <x>, it would return ... <internal-virtual-interface> ... instead of ... dev lo ...

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    please add relevant configurations/commands issued. – Rui F Ribeiro Jan 22 '18 at 23:55
  • @RuiFRibeiro Anything specifically you need? I don't have anything exactly relevant, as my specific need is to force my machine to send an ARP reply if it receives an ARP request for a hardcoded IP Address. – stoneman_41 Jan 23 '18 at 0:00
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    It is your problem, not mine. I advise investing some time on it and documenting it properly for attracting good answers. – Rui F Ribeiro Jan 23 '18 at 0:17
  • @RuiFRibeiro I had added some extra information about what I am running prior to my last response. I understand it is my problem, but what I meant was if there was anything else you needed that could help, with all due respect. – stoneman_41 Jan 23 '18 at 0:22
  • Please define "internal virtual interface". How did you set up these? – Johan Myréen Jan 23 '18 at 6:39

Use arp:

# arp -Ds eth0 pub

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