@adminproconer said in Firewall rule problems. (Client-to-client forward): Where should I start troubleshooting the issue? With the network settings and firewall config of the concerned device. Ensure that all devices in both subnets use pfSense as gateway. If you can access a device from within it's own subnet, but not from another network segment check its firewall and ensure that it allows access from outside.

@adminproconer And how about you remove the link aggregation.. If still slow then I would sniff - but if you have full speed, and ping is 1ms - your issue is not network related, but most likely server or performance related. Sniff to see what is slow, nothing the network the router can do if server answers slowly.