Any Linux can basically be made a good, secure server, depending on your skill and experience. Are you new to Linux/Unix? How much experience do you have with networking in general?
You'd appreciate Mandrake or Suse then. Both have preconfigured security layouts for varying levels of necessity. On Mandrake, choose either the "high" or "higher" default setting to start with. Make sure you install digitally signed only versions of any software you'll need for whatever you'll be serving (i.e. Apache, SMB, NFS, SSH, etc.). In other words, get software directly from the vendor, not from unknown sources.
tnx a lot :good: ......what is the price range though and also do you have any link for mandrake or suse???/
If you want corperate support, you'll have to pay for it. It's substantially cheaper than 2003 Advanced Server though, and has much more relaxed licensing. However, I find the free GNU versions to be sufficient for my needs. In other words, you only have to pay if you want corperate support; the OS itself is free. You can download Mandrake here, and Suse here.