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pedinopa_170325's avatar
pedinopa_170325
Icon for Nimbostratus rankNimbostratus
Dec 27, 2017

incomplete ARP

I have a simple virtual F5 install with a single F5 LTM, 1 node, 1 pool, 1 VS. I am having routing issues and noticed in my ARP table there is an incomplete ARP. the address is my gateway, but the ...
BIG-IP
devops
TMSH
Hamish's avatar
Hamish
Icon for Cirrocumulus rankCirrocumulus
Dec 28, 2017

An incomplete ARP means that the BigIUP needs to route via the gateway, and has sent an ARP request to resolve the IP to the physical address, and has not received a response.

 

Without the ARP entry completing (i.e. A response recieved) the BigIP won't send traffic via the gateway, so yes, this is an issue, and yes this is why you don't see traffic (Assuming the routing tables are correct, etc etc).

 

Things to check

 

  • Are you really on the same VLAN?
  • Can you see the ARP request leaving the correct interface being broadcast on the VLAN?
  • Can you see the ARP response anywhere? (tcpdump is your indispensable friend here)
  • Going out on a limb, but check there's no firewall, or ip filters on your gateway that would stop the traffic.