Testing a Postfix Configuration
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Manually Testing Connection
Testing (like this) can (as far as I've found) only be done with non-TLS setups. There's something about the postfix connection that doesn't play nice with 'openssl s_client'. AFAIK, the only way to test a TLS setup is to use a mail agent like Thunderbird.
Example One
To test the server side, connect (for example, with telnet) to the Postfix SMTP server port and you should be able to have a conversation as shown below. Information sent by the client (that is, you) is shown in bold font.
$ telnet server.example.com 25 . . . 220 server.example.com ESMTP Postfix EHLO client.example.com 250-server.example.com 250-PIPELINING 250-SIZE 10240000 250-ETRN 250-AUTH DIGEST-MD5 PLAIN CRAM-MD5 250 8BITMIME AUTH PLAIN XXXXXXXXXXXXXXXX 235 Authentication successful
Instead of XXXXXXXXXXXXXXXX, specify the base64 encoded form of \0username\0password (the \0 is a null byte). The example above is for a user named `test' with password `testpass'.
In order to generate base64 encoded authentication information you can use one of the following commands:
% printf '\0username\0password' | mmencode
% perl -MMIME::Base64 -e \
'print encode_base64(\0username\0password);'
Example Two
telnet localhost 25 Trying ::1... Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. 220 something.fake ESMTP Sendmail 8.12.11/8.12.11/SuSE Linux 0.6; Wed, 2 Apr 2003 15:13:01 -0700 EHLO localhost 250-something.fake Hello localhost [127.0.0.1], pleased to meet you 250-ENHANCEDSTATUSCODES 250-PIPELINING 250-8BITMIME 250-SIZE 250-DSN 250-ETRN 250-AUTH LOGIN PLAIN 250-DELIVERBY 250 HELP AUTH LOGIN 334 xxxxxxxx xxxxxxxx 334 xxxxxxxx xxxxxxxx 235 2.0.0 OK Authenticated MAIL FROM: me@something.fake 250 2.1.0 me@something.fake... Sender ok RCPT TO: you@nowhere.land 250 2.1.5 you@nowhere.land... Recipient ok DATA 354 Enter mail, end with . on a line by itself This is a test . 250 2.0.0 xxxxxxxx Message accepted for delivery QUIT 221 2.0.0 something.fake closing connection Connection closed by foreign host.
Testing for Open Relay
telnet mail.foo.com 25 Trying 255.255.255.255... Connected to mail.foo.com. Escape character is '^]'. 220 mail.foo.com ESMTP Postfix HELO foo.com 250 mail.foo.com MAIL FROM:zane@foo.com 250 2.1.0 Ok RCPT TO:atestaddress@yahoo.com 554 5.7.1 atestaddress@yahoo.com: Relay access denied
Good!
