These small maps makes running Portal MP server easier.
Extract maps to C:\Program Files\Steam\steamapps\<Your Steam Account Name>\Portal\portal\maps\
If you want to invite your friends, it's posible through Steam, but if it's not working, type status into console and tell an IP to your friend.
Screenshots:
To start the server, type the following commands:
sv_cheats 1
sv_lan 0
maxplayers 32
deathmatch 1
net_start
map portal_servertest1
deathmatch 1
net_start
disconnect
maxplayers 32
map portal_servertest2