Re: Upstream Router ARP Problem

Hello,

-----original packet-----
00:c0:89:1b:04:c3 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 60: arp who-has 109.3.4.88 tell 217.2.1.81

Your upstream router uses sender protocol address that is on a different subnet than 109.3.4.88.

This ARP request won't be replied to unless You configure proxy ARP 

https://kb.juniper.net/InfoCenter/index?page=content&id=KB26906 

https://www.juniper.net/techpubs/en_US/junos14.1/topics/concept/interfaces-restricted-unrestricted-proxy-arp-overview.html

Best course of action would be to fix Your upstream provider but in the meantime please add this line to the config:

set interfaces reth0.0 proxy-arp restricted ## You can try unrestricted as well

Then re-test and report back.

HTH

Thx
Alex