FcRDNS requires a PTR record to exist such that the rDNS of an IP maps back to a name that itself maps to the same IP. "Forward-confirmed Reverse DNS".

If I have an Exchange server sitting behind a dual-WAN device such as a 2960, I know I can configure a load-balancing policy to force all outgoing SMTP traffic over WAN1, so that its HELO will match the name associated with the WAN1 IP which, in turn, resolves back to that name, but if I wanted to employ a fail-over configuration instead, this would cause problems because I can configure the HELO from Exchange to match the WAN1 IP, as above, but if the device failed over to WAN2 the HELO would no longer match the name.

I can imagine a scenario in which the Exchange server is multi-homed, has a different private IP on WAN1 from the one on WAN2, and knows to use a different HELO on each IP, but this relies on a few things that may consign the idea to the waste-basket:

• Exchange being able to be multi-homed


• Exchange being able to issue a different HELO on each multi-homed IP


• The Vigor being able to multi-home in this way

Has anyone come across a solution to this, or a better solution to the whole fail-over Exchange issue?

Thanks in advance for any ideas.