Hi Simon, On Sun, 2022-09-04 at 21:22 +0100, Simon Hobson wrote: > declassed art via Dng <dng@lists.dyne.org> wrote: > > > I do have an unconfigured PTR for a couple of reasons, one > > of those is lack of static IP for now. > > I figured out quite quickly that checking reverse DNS is a waste of > time - too many systems, even those run by professional > network/server engineers, are just badly configured. > My experience (running a small family mail server on the premises, but of course with a fixed IP - I'm with Zen in the UK) is the opposite of this.
I configure strict postfix rules that incoming mail should have a reverse DNS. Here's my recent traffic: 3490 received 3444 delivered 43 forwarded 1 deferred (1 deferrals) 0 bounced 1799 rejected (34%) Of those rejected: 974 Cannot find your reverse hostname 283 Helo command rejected: Host not found 251 Cannot find your hostname 23 Helo command rejected: need fully-qualified hostname 16 Recipient address rejected: User unknown Message that pass my postfix filters are then scored by my spamfilter rspamd: 222 Rejected by rspamd (mix of 4.7.1 try again later or 5.7.1 spam message rejected). In practice most greylisted 'try again laters' that do try again then end up in the users spam folders for them to evaluate and if necessary recategorise. So checking for a valid reverse DNS is my most effective filter. Only very rarely is it rejecting mail from anyone I'm expecting mail from: by inspection they are all obvious spam addresses and of course if they have a genuine reason to email me they are getting the message that their mail isn't getting through because they have no reverse DNS. -- Marjorie _______________________________________________ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng