3.2. Traversing a Firewall

To use UM across a firewall, several port options may need to be changed. The options of interest include:

• Multicast resolver: resolver_multicast_port.

• Unicast resolver: resolver_unicast_port, resolver_unicast_port_low, resolver_unicast_port_high, and resolver_unicast_destination_port.

• TCP transport: transport_tcp_port_low and transport_tcp_port_high for contexts, and transport_tcp_port for sources.

• LBT-RM transport: transport_lbtrm_source_port_low, transport_lbtrm_source_port_high for contexts, and transport_lbtrm_destination_port for sources.

• LBT-RU transport: transport_lbtru_port_low and transport_lbtru_port_high for contexts, transport_lbtru_port for sources, transport_lbtru_port_low and transport_lbtru_port_high for receivers.

• Multicast immediate messaging: mim_destination_port, mim_incoming_destination_port, and mim_outgoing_destination_port.

• Requests: request_tcp_port, request_tcp_port_low, and request_tcp_port_high.

In addition, since machines acting as a firewall are often multi-homed as well, consult the section on Configuring Multi-Homed Hosts for additional considerations.