Mail Relay Testing

For mail hubs that found themselves a victim of spammers you can check if the relaying is accidentally enabled using MAPS Transport Security Initiative. For testing see Is my mailer vulnerable For fixing information How can I fix the problem. You need to keep your MTA up-to-date. Holes in both sendmail (upgrade to v. 8.12.3 or later is recommended) and IMAP can be used to get root access -- see Relaying of Spam Email through Victim Sites . For sendmail 8.9 some discussion is in Using check_ in sendmail 8.9. For 8.8 in Anti-Spam Provisions in Sendmail 8.8.

Bridge wrote:
> Want to get some detail adive on how to test the that the sendmail daemon running on the is relay disabled? I understand that sendmail 8.9 disabled relay by default, is there a way to test it? Please give some detail. I also would like to have some details on how to prevent sendmail from spam.

Start a shell, then:

$ telnet your_mail_server_name 25
HELO
MAIL FROM: user1@domain1
RCPT TO: user2@domain2

If your mail server has been configured properly, it will say something
about being unable to relay email.

Anonymous

Copyright © 1996-2009 by Dr. Nikolai Bezroukov. www.softpanorama.org was created as a service to the UN Sustainable Development Networking Programme (SDNP) in the author free time. Submit comments This document is an industrial compilation designed and created exclusively for educational use and is placed under the copyright of the Open Content License(OPL). Site uses AdSense so you need to be aware of Google privacy policy. Original materials copyright belong to respective owners. Quotes are made for educational purposes only in compliance with the fair use doctrine.

Disclaimer:

The statements, views and opinions presented on this web page are those of the author and are not endorsed by, nor do they necessarily reflect, the opinions of the author present and former employers, SDNP or any other organization the author may be associated with.
We do not warrant the correctness of the information provided or its fitness for any purpose
In no way this site is associated with or endorse cybersquatters using the term "softpanorama" with other main or country domains (e.g. softpanorama.com) with bad faith intent to profit from the goodwill belonging to someone else.

Last modified: August 14, 2009