> On 3 May 2026, at 03:11, Miles Fidelman via mailop <[email protected]> wrote: > > Hi Folks, > > I'm busily migrating an old server to a new one, and in the process losing a > bunch of IP address ... so now I'll be sending mail for multiple domains out > of the same IP address. > > It's been a while, and what with DKIM & DMARC and all, I've lost track of the > details. So I wonder if someone might offer some quick advice on configuring > one server as the outgoing server for multiple domains, all behind a single > IP. > > Specifically, since I need to set up a PTR to point to the server, any > suggestions on how to set up the DNS records for other outgoing domains - so > that DMARC works properly?
You set it up exactly the same as if they were on different outbound IPs. The PTR record just needs to be something that indicates it’s outbound mail. We have at least 4 domains coming off a single IP address and the PTR is a different domain completely. Mail delivery is fine. The rules for the PTR is “mail” “mx” “smtp” or something that indicates this is intentionally an outbound mail server and there if FcrDNS (which I’ve heard both as “full circle reverse DNS” and “forward confirmed reverse DNS”). But the concept is identical: IP points to a hostname and the hostname points back to the same IP address. laura -- The Delivery Expert Laura Atkins Word to the Wise [email protected] Delivery hints and commentary: http://www.wordtothewise.com/blog
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