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s1mple

Member

Registered: 2023-11-13

Posts: 5  

lists.dyne.org require rDNS for senders

Hello there!

I'm running my own mail server and I can't join any mailing lists on lists.dyne.org, because the SMTP server can't find a reverse DNS entry for the IP that makes it happy. Anyone can verify that both the A and MX record of the domain point to the IP address and that SPF and DKIM checks out. I have since setup reverse DNS, but it didn't seem to make a difference and it's not always an option for selfhosters.

I also had problems before, when my server's IP (another server I had), was part of an IP block that was nulled by your DNSBL filter, because another IP in that range had sent out spam. The issues was resolved between the DNSBL and the host after a while, but the disruption was noticeable. I hope you'll consider making your mailinglists more accesible to self-hosters, so that people don't just give up and go with big tech who always stay clear of these issues.

I realise I might be more open than most mailserver admins are willing to, but I myself don't lookup any reverse DNS information on my SMTP server or require DKIM or SPF, because I believe that anyone with a telnet client should be able to connect to my SMTP and send an e-mail. I'm not saying everyone else should go that far, but I think requiring rDNS is too strict.

The most fair and efficent approach I know of to prevent spam, while being friendly to genuine senders, is a bayes filter trained on incoming e-mail, it would both learn about trusted IPs and content to classify e-mail. In the context of mailing lists, one would put the messages marked spam with some not very high probability score in a moderation queue, to be checked manually.

Thanks for listening, and I hope I'll see you all soon on the mailing lists.

smpl

golinux

Administrator

Registered: 2016-11-25

Posts: 3,283  

Re: lists.dyne.org require rDNS for senders

Sadly, there is nothing that Devuan can do because Dyne admins the backend of their mailing lists.

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s1mple

Member

Registered: 2023-11-13

Posts: 5  

Re: lists.dyne.org require rDNS for senders

Thanks, I'll see if I can find some other way to contact those who run the mail servers.

ralph.ronnquist

Administrator

From: Battery Point, Tasmania, AUS

Registered: 2016-11-30

Posts: 1,218  

Re: lists.dyne.org require rDNS for senders

I had a quick look and apparently neither of mx1 or mx2 of your domain are in the domain's spf.
Aren't those the mailout hosts? Or should spf include an "a" or its ip to indicate itself, if that's your mailout host (and host ...7 doesn't have rdns)

s1mple

Member

Registered: 2023-11-13

Posts: 5  

Re: lists.dyne.org require rDNS for senders

That's interesting. The address I had to use to be able to sign up for the forum was an e-mail with a free provider and not my own. The ~all in the SPF is a softfail for other IP addresses. On my server I use hardfail for IPs other than those of the mx records v=spf1 mx -all. I've just managed to send an e-mail to hackers@dyne.org with that same e-mail address, so apparantly the SMTP is more lax with SPF than it is with rDNS.