What OS are you running on your server? Can the clients access the server (shared folders or pinging) if the firewall is on? What firewall program are you using?
You will need to configure your firewall software to allow access from these client computers. basically Firewall turns off many ports that are required for connection. Just open those ports for clients and they will be able to access your server.
_________________________________________________________
Solution provided by
Sheraz - Network Support Analyst
Civnom Technologies
civnom.co.uk