I just set up my first ever email server and I’m proud of myself! 😊 Do you have any advice to avoid common problems? I mean something beginners often do that they shouldn’t. Thanks!

  • z3braEnglish
    25•1 year ago

    Congratulations! A mail server is quite demanding in terms of initial setup, but it’s also very rewarding !

    Here are a few pointers I can give you:

    • Using a good domain is important, some provider block entire TLDs for cheap domains (eg. .tk or .pw). I learnt it the hard way…
    • Set your MX records to A records, not CNAME
    • Ensure your PTR records match your A records for the mail server
    • Learn about SPF and DKIM
    • Set them up, and verify with mxtoolbox
    • Use the ip4: and/or ip6: selectors for SPF
    • Setup a spamfilter (I like spamassassin)
    • Leave it all running for a few weeks/months
    • Publish a DMARC policy on your DNS, and verify with mxtoolbox

    This should limit a lot your likeliness to end up in spam folders (which is usually the hardest part about running your mail server)

      • z3braEnglish
        1•1 year ago

        Because it’s the simplest form of mechanism for SPF, and the most understandable in my opinion.

        a and mx mechanisms are just ip4/ip6 with extra resolving steps and more complex rules. For a selfhosted setup where you only have a single IP address, this is the most straightforward

        As an example, try to guess which one of these SPF records will or will not pass SPF, given that the IP address sending emails is 1.2.3.1:

        $ORIGIN domain.tld.
$TTL 1d

@        SOA      pluto.domain.tld. admin.domain.tld ([…])
          NS      pluto.domain.tld.
          NS      saturn.domain.tld.
          MX 10   mx.domain.tld.
           A      1.2.3.5
         TXT      "v=spf1 a -all"
         TXT      "v=spf1 mx -all"
         TXT      "v=spf1 ip4:1.2.3.1 -all"

jupiter    A      1.2.3.1
pluto      A      1.2.3.2
saturn     A      1.2.3.3
venus      A      1.2.3.4

mx     CNAME      jupiter.domain.tld.