Ok well, we moved to a dedicated server few weeks ago but we got a weird problem.

We are running a software where users can connect to through port 6112 (UDP). The problem is that this port was blocked but our host opened it for us. Now it works for most users but some people still have UDP problems when they connect so it doesn't work for them.

Those people can connect to the exact same sofware on other servers and they were able to connect our software before we move to this server. Our previous host was on Red hat but we are using FreeBSD on this one. Is it possible that it is the cause? Maybe FreeBSD comes with a firewall or something? (I am not too used to freeBSD).

Any other idea? I am a bit lost because our host really say that port 6112 (UDP) is open but it still block people that wew not blocked before we use this host :/

Thanks much.

Check and see if any of them were blocked in the firewall due to previous attempts to connect.

The idea of propagation came to mind, but that is only for DNS. When did the port get opened up?

The port was opened 2 days ago.

Hmmmm... how can I check if any of them are blocked in the firewall exactly?

Which firewall do you use? Typically, firewalls have a file similar to hosts.deny or some such. APF has /etc/apf/deny_hosts.rules.

Jakiao, he use FreeBSD. By default FreeBSD do not use any firewall.

killer15669, I reccomend ask DC about port filtration, they can endable it for pervent ddos.

andreyka: It is not illogical to think that he may have -installed- his own firewall?