telnet localhost 25

Result

Trying 127.0.0.1…
Connected to localhost.
Escape character is ‘^]’.
220 mail.sharewiz.net ESMTP exim
ehlo client
250-mail.sharewiz.net
250-PIPELINING
250-SIZE 10240000
250-ETRN
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN

% openssl s_client -starttls smtp -connect mail.sharewiz.net:25

Result

250 DSN
ehlo client
250-mail.sharewiz.net
250-PIPELINING
250-SIZE 10240000
250-ETRN
250-AUTH PLAIN LOGIN
250-AUTH=PLAIN LOGIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
auth login
334 VXNlcm5hbWU6
Y2xlbWVudEBmb3J1bWFuYWxvZ3VlLmZy
334 UGFzc3dvcmQ6
Q2xlbWVudDAx
DONE

apt-get install swaks libnet-ssleay-perl

Test the connection:

swaks -a -tls -q HELO -s localhost -au your_user -ap '<>'

Result

 === Trying localhost:25...
 === Connected to localhost.
 <-  220 debianwb ESMTP Exim 4.76 Thu, 04 Aug 2011 14:22:02 +0600
  -> EHLO debianwb
 <-  250-debianwb Hello localhost [127.0.0.1]
 <-  250-SIZE 52428800
 <-  250-PIPELINING
 <-  250-STARTTLS
 <-  250 HELP
  -> STARTTLS
 <-  220 TLS go ahead
 === TLS started w/ cipher DHE-RSA-AES256-SHA
  ~> EHLO debianwb
 <~  250-debianwb Hello localhost [127.0.0.1]
 <~  250-SIZE 52428800
 <~  250-PIPELINING
 <~  250 HELP
  ~> QUIT
 <~  221 evie closing connection

Note that above we are sending an empty password while testing with the swaks tool.

Sending a mail from command line with:

echo "Test" | mail -s Testmail foo.bar@gmail.com

or

exim -bt recipient@address

to see what Exim thinks should be done with a particular address, and add -d to the command-line to get more debugging information (but beware that there can be a lot to pick through).

Succesful logs would have something like

2011-01-01 20:45:24 1PZ7OG-0001Vp-Rx <= root@gustav U=root P=local S=360
2011-01-01 20:45:26 1PZ7OG-0001Vp-Rx => foo.bar@gmail.com R=dnslookup T=remote_smtp H=gmail-smtp-in.l.google.com [209.85.229.27] X=TLS1.0:RSA_ARCFOUR_MD5:16 DN="C=US,ST=California,L=Mountain View,O=Google Inc,CN=mx.google.com"
2011-01-01 20:45:26 1PZ7OG-0001Vp-Rx Completed

Unsuccessful logs would have something like:

2011-01-01 20:50:08 1PZ7Sq-0001X9-L4 <= <> R=1PZ7Sq-0001X7-Jo U=Debian-exim P=local S=1780
2011-01-01 20:50:11 1PZ7Sq-0001X9-L4 => newsletter@foo.bar R=dnslookup T=remote_smtp H=mx1.emailsrvr.com [98.129.184.3] X=TLS1.0:RSA_AES_256_CBC_SHA1:32 DN="C=US,O=mx1.emailsrvr.com,OU=GT21850092,OU=See www.geotrust.com/resources/cps (c)08,OU=Domain Control Validated - QuickSSL(R),CN=mx1.emailsrvr.com"
2011-01-01 20:50:11 1PZ7Sq-0001X9-L4 Completed

The R= is saying that this item is a bounce and the message-id given in the R= part is the original message-id which failed. You'll need to look at the log-entry for that to see what recipient address was generated and why it failed.

IPs may be different so run dig smtp.sharewiz.net and use the IPs it returns instead.

Add this to bind or into /etc/hosts

/etc/hosts

123.123.123.123 smtp.sharewiz.net

Save this to a PHP file, replacing test@example.com with an email address you control.

#!/usr/local/bin/php
<?php
while (true) {
  mail('test@example.com', 'Test email deletethiswithafilter', 'test ' . time());
  usleep(500000);
}

If the earlier dig command returned multiple IPs then save this to a PHP file and run it while the above is running also. Every 5ms - 15ms it will toggle the entry in the hosts file for smtp.sharewiz.net between the two IPs that it resolves to for example 123.123.123.123 and 234.234.234.234.

#!/usr/local/bin/php
<?php
while (true) {
  passthru('new_hosts_file_contents=`cat /etc/hosts | sed \'s/123.123.123.123/ip123/g\' | sed \'s/234.234.234.234/ip234/g\' | sed \'s/ip123/234.234.234.234/g\' | sed \'s/ip234/123.123.123.123/g\'`; echo "$new_hosts_file_contents" > /etc/hosts 2>&1');
        usleep(10000 + rand(-5000,5000));
}

NOTE: hosts_require_auth = * and hosts_require_tls = * also works if IPv6 support isn't needed.