If you are having problems with a port forward, try the following.
1. If you did not exactly follow the How can I forward ports with pfSense? guide, delete anything you have tried, and start from scratch with those instructions.
2. Port forwards do not work internally unless you enable reflection. Always test port forwards from outside your network.
3. If you're still having problems, edit the firewall rule that passes traffic for the NAT entry, and enable logging. Save and Apply Changes. Then try to access it again from the outside. Check your firewall logs to see if the traffic shows as being permitted or denied.
4. Use tcpdump to see what's happening on the wire. This is the best means of finding the problem, but requires the most networking expertise. Start with the WAN interface, and use a filter for the appropriate protocol and port. Attempt to access from outside your network and see if it shows up. If not, your ISP may be blocking the traffic, or for Virtual IPs, you may have an incorrect configuration. If you do see the traffic on the WAN interface, switch to the inside interface and perform a similar capture. If the traffic is not leaving the inside interface, you have a NAT or firewall rule configuration problem. If it is leaving the interface, and no traffic is coming back from the destination machine, its default gateway may be missing or incorrect, or it may not be listening on that port. For certain types of traffic you may see return traffic indicating the host is not listening on that port. For TCP, this would be a TCP RST. For UDP, it may be an ICMP Unreachable message.
1. NAT and firewall rules not correctly added (see How can I forward ports with pfSense?). Hint: You probably do NOT want to set a source port.
2. Firewall enabled on client machine.
3. Client machine is not using pfSense as its default gateway.
4. Client machine not actually listening on the port being forwarded.
5. ISP or something upstream of pfSense is blocking the port being forwarded
6. Trying to test from inside your network, need to test from an outside machine.
7. Incorrect or missing Virtual IP configuration for additional public IP addresses.
8. The pfSense router is not the border router. If there is something else between pfSense and your ISP, you must also replicate port forwards and associated rules there.
9. Forwarding ports to a server behind a Captive Portal. You must add an IP bypass both to and from the server's IP in order for a port forward to work behind a Captive Portal.
10. If this is on a WAN that is not your default gateway, make sure there is a gateway chosen on this WAN interface, or the firewall rules for the port forward would not reply back via the correct gateway.
11. If this is on a WAN that is not your default gateway, ensure the traffic for the port forward is NOT passed in via Floating Rules or an Interface Group. Only rules present on the WAN's interface tab under Firewall Rules will have the reply-to keyword to ensure the traffic responds properly via the expected gateway.
12. If this is on a WAN that is not your default gateway, make sure the firewall rule(s) allowing the traffic in do not have the box checked to disable reply-to.
13. If this is on a WAN that is not your default gateway, make sure the master reply-to disable switch is not checked under System > Advanced, on the Firewall/NAT tab.
14. WAN rules should NOT have a gateway set, so make sure that the rules for the port forward do NOT have a gateway configured on the actual rule.