Furuno Felcom 250 Service Manual page 230

3) DST. Address, From address
Note that Network IP address cannot be specified.
When the direction is set to WAN -> LAN,
specify the IP address for the LAN PC/server for the "DST. address", and specify the
sender's address for the From address.
If you do not specify any address for the "From address" field, you will be receiving
all packets from any sender address.
When the direction is set to LAN -> WAN,
specify the IP address for the WAN for the "DST. address", and specify the address of
the receiving PC (server) for the From address.
If you do not specify any address for the "DST. address" field, you will be receiving
all packets from any sender address.
4) Protocol
All:
Packets for all protocols.
ICMP:
This stands for Internet Control Message Protocol, and it prohibits responses
to be made for Ping commands made from the outside.
Any:
Specify the protocol port numbers for those other than the UDP and TCP
protocols.
TCP/UDP, TCP, UDP:
Select the protocol between those for TCP/UDP, TCP, or UDP.
For instance, when port number of "25" is specified, set as 25 - 25.
When you have completed the settings, click Add, and the settings will be added to the
IP filter list.
8-4
8.1 Security Settings