Reference Manual


umap - maintain the UDP Port Table
umap [add|delete dst_port_range [src_port]]


Command umap is used to add or delete UDP port numbers used by applications such as ICQ (port 4000) and Battle Net (port 6112).

Umap with no arguments prints the current contents of the UDP Port Table.

NAT32 handles mapping of UDP packets sent to the Internet on ports in the UDP Port Table as follows: This mechanism allows UDP applications which rely on port mappings to be permanent (e.g. ICQ, Battle Net and others) to function correctly on machines behind the  NAT32 gateway.
Note that the mechanism differs from the Permanent Port Mapping Mechanism in the following way:
Games which use Battle Net often require that the source port number of UDP packets be preserved. Such games usually use the same source and destination port number (6112). Also note that a ppmap command is still needed, because unsolicited UDP packets are constantly being sent to the machine running the game.
The following ppmap command could be used:
ppmap add udp 6112 IP_Addr 6112
Games which send a continual stream of UDP packets from an unknown source port to a fixed destination port could use the following umap commands to preserve the source port number:
umap add 9000 1
umap add 9001 1
pmap, ppmap, setb