This post was published 4 years 11 months 19 days ago. Therefore, it may well be out of date. Do not reply on the contents of this post being accurate. In episode 79 of Security Now (15/02/07), brought to you by the TWiT network, Steve Gibson and Leo talk about spam and spambots. They discuss the details of eMail “Received:” headers and explain how the examination of those headers can penetrate any spoofing to reveal the true originating IP of any spoofed spam eMail.
During the show Steve also talks about DNSstuff.com. This is a really useful site with loads of information and some great free tools (and some advanced tools if you subscribe). It’s well worth checking out for all things DNS.