SMTP2GO notes on setup - DNS record verification seeming to take a
long time - fixed
reddit / selfhosted

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Geminii27 · 2023-10-07 18:13

Just a note for anyone setting up a SMTP2GO account as an external
SMTP relay for a self-hosted email server:

I set one up and it all worked correctly (once I figured out what
settings to alter on my own end). The only hiccup I encountered was
after adding to my domain's DNS records with the additional
'verification' records SMTP2GO wanted. After doing so, it seemed like
it was taking a very long time for SMTP2GO to verify the records, even
though I kept clicking the 'Verify' button on their site (in the
dashboard) every so often.

As it turned out, if you copy the required records *as-is* (using the
admittedly somewhat convenient 'Copy' button provided on the web
interface, or even just copy-and-pasting), and update your DNS records
using that exact text, sometimes the DNS record - depending on your
DNS provider's interface - will be published with an extra copy of the
domain name affixed to the entry. So your record that you entered as,
for example, generatedstring._domainkey.**mydomainname.tld**, will
actually be published as
generatedstring._domainkey.**mydomainname.tld.myhostname.tld**,
because your DNS provider will automatically add the domain name to
the end of the record. HALPING!

And while, yes, SMTP2GO does actually have notes on this happening,
and how to correct it, and it even detects when this is happening
(handy), it doesn't actually tell you automatically after you hit the
'Verify' button - you need to hover over the red (!) icon near one of
the entries to get the explanation. Or at least that's what I found.

So if you think that your DNS record verification is taking *way* too
long, hover over that red error to see if that's what's happening, and
if so, change all your new DNS entries from
generatedstrings._domainkey.**mydomainname.tld** to just
generatedstrings._domainkey (or whatever they are when you take the
domain name off), and try again. Might save you some time and
frustration.

That little... minor frustration aside, everything seems to be passing
testing so far. And I've got a setup where my email clients hook into
a local Linux box running postfix, which then in turn passes stuff out
to SMTP2GO on the external leg as a relay without setting up SMTP2GO
individual mailboxes (those are all self-hosted), so there was some
screwing with the main.cf and sasl_passwd files to make everything
work, or any attempt to send email gave a 550 error.

 

(For those from the future searching for the details, they are:)
/etc/postfix/main.cf:
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_auth_enable = yes
smtp_sasl_security_options =
relayhost = [mail.smtp2go.com]:587

/etc/postfix/sasl_passwd:
[mail.smtp2go.com]:587
SMTP2GO_account_username:SMTP2GO_account_password

Then run:
postmap /etc/postfix/sasl_passwd
postfix reload

 

Even so... all things considered, not bad. A lot easier to set up
after the first time through; most of the faffing about was reading
troubleshooting guides and poring through SMTP logs; the actual
changes I ended up having to make were relatively light and could be
done in a few minutes.