Reference Manual

NAME

pmap - control port mapping

pmap [ifn|all [on|off]]

pmapc ip

Command pmap turns port mapping for the specified interface (or for all interfaces) on or off. If no arguments are specified, the current state of the port mapping table is printed as follows:

Index   - the table index
Ifn     - the Interface for which the mapping is valid
IPsrc   - the source address being mapped
IPdst   - the destination address of the mapping
Prot    - the protocol type (UDP or TCP)
Dp      - the destination port for the mapping
Sp      - the source port being mapped
Nsp     - the mapped port number
TTL     - the time-to-live (secs) for this entry
Ssff    - the SYN and FIN flags for TCP mappings
Traffic - the number of packets sent via this mapping

Port mapping is used to map multiple private IP addresses to a single registered IP address. IP address mapping must be on.

Outgoing packets are port-mapped only if their source port numbers are greater than 1024. This allows replys from servers running on the address-mapped host to be transmitted correctly.

Whenever possible, the original source port number will be preserved. A new source port number is only generated if some other host is already using the original source port number.

Incoming packets are port-mapped as needed to allow forwarding of replies to the original host.

Incoming packets with a port number contained in the Permanent Port Mapping Table are forwarded to the host and port number specified in that table.

Incoming packets with a mapping already in the Port Mapping Table are unmapped normally. For incoming UDP packets, such mappings usually expire after 60 seconds, unless the mappings was made permanent by adding the client application's destination port to the UDP Port Table.

Command pmapc clears all entries for a specified private machine.

Private hosts can use the ping and traceroute utilities transparently. The needed mappings are added automatically and can be viewed with the icmap command.

icmap ipmap ppmap umap