GMOD Dedicated Server Issue

[Evoicefire]

Okay I have two computers one I use for playing GMOD the other is a CentOS server, now I can get the server running etc, but whe i pin the server from my client i get no response. Although when I ping the client from the server I have 0% packet loss. This is really strange. Any help would be appreciated

ALSO
I cannot connect to the Gmod server from my client eg. Client /> CentOS server

so the Client doesn't connect. This is when i pinged the server from my client and got no response.