Keep servers running in the background

[Dibbles]

You can do one of two methods,

A) use Screen - as stated above...
B) add & at the end of your config line...

e.g. ./srcds_run -game cstrike +ip 000.000.000.000 +port 27015 +maxplayers 14 +map map_name -autoupdate &

that will allow you to exit putty and keep your server(s) running.