Something that has always limited the propagation of custom maps has been the lack of support for custom map resources. Running a custom map that has it's own .wad file, custom sprites, or precached sounds has been more of a burden than a pleasure for server operators.
With the next Half-Life release (the client version number will be 18.104.22.168) we're adding in support for custom resource downloading. This is how it works:
For this example let's assume we have a Team Fortress map called "mymap.bsp". This map uses a few different custom resources. It has it's own .wad file called "mytextures.wad", a new model called "mymodel.mdl", and a new sprite called "mysprite.spr". As a server operator you will need to go through these steps to allow these resources to be downloaded:
1. Create a file called "mymap.res" and place it into the tfcmaps directory. The .res file must be the same as the .bsp name.
2. Add the resource names relative to the game directory in this file. The file should look like this:
3. Run your server with sv_allowdownload set to 1.
When a client connects they will start downloading these files. The client's download speed/bandwidth is throttled according to their rate.
There should be some more information on the next Half-Life update here soon, and we'll be posting the information on the next server release to these mailing lists first. We're still likely a week or so away. Een week dus nog, es kijken of ze dat halen...