Posted by Jack Porter over at the Unreal Technology Site:
All server admins running version 2206 demo servers should download this
replacement
IpDrv.dll (62KB) which addresses a denial-of-service attack.
Thanks to Auriemma Luigi at PivX for reminding me that the UT2003 demo had not
been patched to address this issue.
We'll have a Linux version in the next day or two.
You heard the man, patch them demo servers!