topic Re: Proxy arps in Firewall and Security Management

Proxy arps

carl_t — Tue, 25 Oct 2022 07:02:29 GMT

Hi Guys

Can anyone tell me when we need to use proxy arps?

If I have a manual NAT rule with hide NAT, but the NAT object is on the same IP range as the outside interface, do I need to use proxy arp?

cheers

Re: Proxy arps

G_W_Albrecht — Tue, 25 Oct 2022 07:30:59 GMT

See sk30197 about when you need it. Symptoms are:

- After creating a Manual Static NAT rule, Security Gateway does not answer the ARP Requests for the Static NATed IP address that was configured in the Manual NAT rule.

- Security Gateway replies to ARP requests with a wrong MAC address, mostly for the NAT traffic.

sk30197: Configuring Proxy ARP for Manual NAT

sk114395: Automatic creation of Proxy ARP for Manual NAT rules on Security Gateway

Re: Proxy arps

Chris_Atkinson — Tue, 25 Oct 2022 07:53:04 GMT

This is the general situation where the gateway would need to be doing proxy-arp correct.

By comparison if the IP addresses were statically routed towards the Gateway as part of a different subnet this isn't necessary.