title: Debug smtp connection
body: <p>I am using the perl module Net::Smtp_auth to send a mail to myself using the web.de SMTP server on port 25 (no encryption). It works well my computer. But I would like to use the same script to send notification messages about finished jobs on a different machine where I don't have root privileges. On this machine I get a timeout for the connection. I wonder in which way the connection is blocked, what might be the reason to block it (prevent spamers?) and if there might be a way to circumvent the problem. I have some linux tools available but no nmap.
  Might the connection be influenced by proxy settings and, if yes, how do I tell it to SMTP_auth?</p>
  
  <p>The perl script is basically the SMTP_auth example from cpan. But I do not expect that it is relevant here:</p>
  
  <pre><code>#!/usr/bin/perl -w
  
  use Net::SMTP_auth;
  
  $message=$ARGV[0];
  
  $smtp = Net::SMTP_auth-&gt;new('smtp.web.de') or die "Failed to open SMTP connection: $!";
  $smtp-&gt;auth('CRAM-MD5', 'adress', 'password');
  
  $smtp-&gt;mail('adress@web.de');
  $smtp-&gt;to('adress@web.de');
  
  $smtp-&gt;data();
  $smtp-&gt;datasend("To: adress\@web.de\n");
  $smtp-&gt;datasend("From: adress\@web.de\n");
  $smtp-&gt;datasend("\n");
  $smtp-&gt;datasend("$message\n");
  $smtp-&gt;dataend();
  
  $smtp-&gt;quit;
  </code></pre>