I'm having a weird problem with my server. The server is inside my network, connected to a 3com switch which is connected to the router that handles the internet connection. The main purpose of the server is to host a php application.

What's happening is that user 1 to 15 in the private network have no problems connecting to the server, when user 16 tries to connect a time out comes out and is unable to connect to the server. It's not just to the php application, but to any service from the server. When the 15 users are using the application, the server doesn't even answer to ping.

I haven't set any special limit in Apache's ini file or MySql and the firewall is being turned off because the server is only to give service to the internal network. Is there a parameter in any of the network's card conf. files that might me causing this ? Or should I suspect from the router's or switches configuration ?

UPDATE. Tomorrow, I'm gonna do some test on the server modifying two kernel params in :

/etc/sysctl.conf

The settings are:

    net.core.somaxconn 

which has the limit on simultaneous network connections to the server and

    kernel.shmmax

which controls the amount of memory the system can use for managing connections.