My ISP (Qwest) recently implemented a brain-dead measure to prevent spam. They require you to check your email before you can send out email.
Of course, this doesn't prevent spam at all -- it only makes it harder if you have a low-volume mail server. Here's what I did to get around this:
$ crontab -e
Add this line:
*/10 * * * * /usr/bin/telnet pop.ptld.qwest.net 110 < /home/mename/bin/script.txt >& /dev/null
Every ten minutes, it connects to port 110, and runs the contents of bin/script.txt
$ cat bin/script.txt