Exim delivers electronic mail, both local and remote. It's the default mail transport agent installed on some Linux systems; it runs on many versions of Unix an

This introduction to networking on Linux now covers firewalls, including the use of ipchains and Netfilter, masquerading, and accounting. Other new topics in th

Helps administrators integrate SpamAssassin--the leading open source tool for fighting spam that helps eliminate spam without affecting legitimate email--into t