On modern firewalls dynamic PAT is mostly the default.
As a clarification:
- Static PAT means, that the same internal host port for outgoing connections is opened and maintained for NAT/PAT on the firewall; so netstat looks like that:
UDP 0.0.0.0:59491 *:* 7208
the corresponding NAT table entry looks like that:
192.168.0.102:2302 -> 81.6.6.89:59491 -> 69.10.30.248:27900
- Dynamic PAT means, on the firewall an arbitrary port maybe used for outgoing ports, so if netstat on the arma3 process looks like this:
UDP 0.0.0.0:59491 *:* 7208
the corresponding NAT table entry might look like that:
192.168.0.102:2302 -> 81.6.6.89:61478 -> 69.10.30.248:27900
Gamespy will report to connecting clients the port shown in the NAT table entry, because it's the port that is cited in the UDP packet header, but on the reverse way to the host PC/DS, the port at the target is not available because it's different behind the dynamic PAT.
The (wrong) public port is reported, even though port 2302 might be open and properly forwarded.