Clean Your Own House
As you no doubt know, the basic responsibility of a network administrator is to manage the portion of the Internet under that administrator's direct control. The administrator's job doesn't stop with just setting up services. An administrator is also responsible to the rest of the Internet for the traffic that spews from their domain into cyberspace, in whatever form it takes. While it is easy to think that one who does not lock down their systems is only in danger from their boss or immediate superiors, the fact is that the Internet has its own ways of self-policing without being centralized.
No law says that other sites must accept traffic from your network. DNSBLs are a perfect example of what can happen if your domain earns a reputation for having huge gaping holes and refusing to fix them. As a result, you can have the boss banging on your office door wondering why nearly every E-mail sent out is being bounced back.
So, in all of your efforts to combat incoming spam, don't forget the basics of making sure that your systems aren't contributing to the problem. Ensure that your mail server is secured against unauthorized relaying, so that spammers can't make it send spam on their behalf. At the same time, secure your mail server against intrusions, since exploiting security vulnerabilities is another way that spammers gain access to machines to use for their purposes. These two actions alone will save you a lot of grief, making it much more difficult for spammers to embarrass you.
Next, remember that spam can emanate from desktops as well, or from any machine on your network. Modern worms like Sobig-F are designed to turn infected workstations into spam relays. You can watch out for this problemand as a handy side effect find out that a machine has been breached by a virus or wormby having your filters check outgoing mail along with incoming mail. Some of the better spam-fighting tools incorporate virus-blocking at the mail server as well. (Of course, preventing viruses and worms from getting to your desktops helps in more ways than just cutting down on spam.)
Keep your own network in good working order, and you'll be doing your part to make the Internet a better place. And, by implementing a solid spam and anti-virus solution, you'll make your users much happier people. Happier users make for happier administrators!
In our next installment, we'll discuss some of the actual tools you can use to accomplish these goals.