As of October 2013 Steam updated to the new Steampipe format which causes clients attempting to connect to a non-Steampipe server to receive the "Steam Validation" error. Servers must update to the new Steampipe format to restore compatibility with the mod.
Due to this update, server admins will only be able to run dedicated servers on Windows as support for the 2006 SDK has not be released for Linux and may be dropped. Many of the current servers (most of which were Linux-based servers) unfortunately had to be dropped. The remaining servers running under Windows should now be updated to the new Steampipe format.
If you are running or would like to run a Windows server, we are updating the website with the latest information on how to setup a Windows-based dedicated server on the website.
Click Here to read the latest working Windows Dedicated Server Guide on the HL2CTF Forums!
How's progress with getting to steam going?
We are making good progress, the mod has been ported to the 2013 SDK and we are approaching the first closed playtest to see what all will need to be fixed under the new SDK. We will be posting announcements on the official progress very soon!
What's the reason for dropping Linux support?
The new SteamCMD for installing servers only has AppID 205 which is the 2006 Source SDK Base with support files for Windows. It would seem that there will no longer be any libraries for Linux servers under the 2006 SDK. We have ported the mod to the 2013 SDK for release as HL2CTF 3.0 (coming soon) which will have support for both Windows and Linux servers as well as a Linux client!