E-mail in or out of server vanishes with no trace or error?

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > Haus of Tech Support > E-mail in or out of server vanishes with no trace or error?

telcoM: Mar 21, 2009; Fallen Rib

AlternateAccount posted:

The e-mail never arrives. Also, I an send e-mail from the outside to a mailbox on my server. I never get any kind of bounceback or error, but it's not showing up in the user's mailbox. Am I missing something obvious?

Does your domain have SPF records in the DNS?
If you're unsure, run (replace example.net with the name of your actual DNS domain):

code:

$ dig +short example.net TXT @8.8.8.8

If you get back a line that starts with "v=spf1", your domain has a SPF record that identifies valid outgoing email servers from that domain.
It might specify IP addresses explicitly, and/or it might include "+mx" indicating that the servers within your domain with MX records associated with them are also valid email senders.
In that case, check the MX records too:

code:

$ dig +short example.net MX @8.8.8.8

If you have set up a SPF record for your domain at some point, and haven't updated it to match your current server installation, that might be where the problem is.

You said you've already checked your IP and domain against blocklists, but have you checked that your server has a valid _reverse_ DNS mapping?

code:

$ dig +short yourhostnameishere.example.net @8.8.8.8

should return your IP address, and

code:

$ dig +short -x your.IP.addr.ess @8.8.8.8

should return the same hostname as you used with the previous command, with an extra dot at the end, like "yourhostnameishere.example.net."

Failing this old test (at least 20 years old at this point!) gets your email treated as "coming from some spammer server that doesn't even have a proper domain registration" - and today, that means your outgoing emails will very likely go to /dev/null without any error reply.

Note that all the "dig" commands I showed here have a "@8.8.8.8" at the end. That tells the "dig" command to contact Google's public DNS server and have it query your domain - this way, you'll get an idea of how your domain actually looks "from the outside". If some of the answers are not what you expect, try the commands again without the "@8.8.8.8" at the end - if the answers change when omitting the "@8.8.8.8", you have found a DNS data propagation problem.

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The Something Awful Forums > Discussion > Serious Hardware/Software Crap > Haus of Tech Support > E-mail in or out of server vanishes with no trace or error?