Table of Contents

Exim4 - Test sending emails

Using Telnet

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

Using openssl

% 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

Using swaks

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 test email

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).

Check the logs for success

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.

Using a PHP script

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.