[Novalug] smtp and sasl

Xavier Belanger firemountain@belanger.fr
Sat Aug 27 08:59:02 EDT 2016


Hi,

> Is it the "auth" or "vrfy" pieces that suggest SASL?

No: VRFY is a command used to ask the server if an address
is valid. Nowadays, this is mostly disabled since it was
used (abused) for a time by spammers to check email addresses
(I'm not sure that is relevant anymore).

The AUTH command is part of the regular SMTP protocol, to specify
what type of authentication mechanisms are used (could be PLAIN,
that is just plain text, or LOGIN, using base-64 encoded strings
for instance). But it doesn't apply on how the information is
transmitted.

SASL is used as a 'wrapper'; you should see some information
in your mail server logs. Here is an example of how it looks like
with Postfix:

Aug 27 06:30:03 server postfix/submission/smtpd[18029]: 1160221FB54: client=client.example.net[192.168.1.2], sasl_method=PLAIN, sasl_username=user@server.example.net

If time permits, I may be able to give you more information on SASL
later this weekend (or someone else may post something more relevant
before me).

Sincerely.
-- 
Xavier Belanger



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