Freeware: Network Tools and antispam software

Anti-spam
K9 - keir.net/k9.html
MailWasher- mailwasher.net/
POPFile - popfile.sourceforge.net/
SpamBayes - spambayes.sourceforge.net/
SpamPal - spampal.org/
Network Tools
CMDTime NTP Utility - softshape.com/download/
Ethereal Protocol Analyzer - ethereal.com/
Gencontrol - gensortium.com/products/gencontrol.html
hamachi - hamachi.cc/
NetMeter - readerror.gmxhome.de/
NetProfiles - netprofiles.danielmilner.com/
NMap - insecure.org/nmap/
Ntop - ntop.org
PingPlotter - pingplotter.com
PuTTY - chiark.greenend.org.uk/~sgtatham/putty
RAS Graph & Stats - forum.flashfxp.com/showthread.php?s=&threadid=2400
RealVNC - realvnc.com/
TightVNC - tightvnc.org/
Ultr@VNC - ultravnc.sourceforge.net/
WinSCP - winscp.com/