ELSA Documentation


Service-table

The use of inverse masquerading makes 'services' (e.g. a file server) selectively visible in the Internet by entering specified ports in the service table in the IP network, while all other services and computers remain invisible from the local network (see also 'IP Masquerading (NAT, PAT)'). The service table (also called the static masquerading table) can contain up to 16 entries and has the following layout:

D-port Intranet-addr.
20 10.1.1.10
21 10.1.1.10

The different columns have the following meaning:

O D-port: Destination port for the particular entry
O Intranet-addr.: Destination IP address for the computer in the local network

Through this assignment, it is possible, for example, to address the relevant service directly via Telnet. Enter the IP address of the router and attach the port number, separated by a double point, to the address.

You can use the command

telnet 192.38.50.100:27

to connect directly to a news server that can be reached via a router with the IP address 192.38.50.100.


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