NEXPEED NR304G-4W User’s Manual
NexComm Systems, Inc. 61 PAGE
Parameters
<local-ip> - Specify an IP address that belong to the private(internal) IP
network.
<lport> - Specify a port number for the internal IP address.
<global-ip> - Specify a shared outbound PAT address.
<gport> - Specify a port number for the outbound PAT address.
Usage Examples:
(conf)# nat entry 192.168.1.1 23 168.126.188.111 23
allows inbound TELNET access for a internal host
192.168.1.1
.
Note1:
A global IP address for the static entry must exist in the address pool for the
PAT translation, before you can set up a "nat entry" command.
Note2:
If the port service is ICMP(ping), enter string "ping" or port "0" in the
fields of the <lport> and the <gport>.
Translation time-out :
NAT has an internal translation table. A translation table entry represents one TCP, UDP,
ICMP connection.(
Note:
a port mapping can generate many TCP and UDP
connections.) A translation table entry is reused as long as traffic includes packets that
match an entry. All the entries for a connection are freed(expire) when the connection
disconnects.
The NR304G-4W unit removes entries from the translation table entries on the basis of
the following timeouts:
> TCP translations time out after 240 seconds
> UDP translations time out after 120 seconds
> ICMP translations time out after 10 seconds
You can manually change timeouts using the following command :
COMMAND
(conf)# nat timeout tcp|udp|icmp <seconds>
Parameters
tcp|udp|icmp : TCP or UDP or ICMP translations
<seconds> - timeout value, set in the unit of second
