VIRATA ADSL Ethernet Router Series, Technical Manual

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A- Commonly Used Commands
A-21
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A.4.2 inbound / Port Address Translation / Port Mapping
Syntax:
nat inbound list
nat inbound add <i/f> <port>/<proto> <new IP> [quiet]
nat inbound delete <#>
nat inbound flush
Description:
This command enables the user to list or to set up a series of rules, to determine
what happens to incoming traffic. By default all incoming packets, other that
packets arriving in response to outgoing traffic, will be rejected.
The
nat inbound add
command allows packets arriving on a specific port and IP
protocol to be forwarded to a machine on the private network.
<i/f>
is an interface
name as shown by the
nat interface list
command;
<port>
is the destination UDP
or TCP port number to match in the incoming traffic;
<proto>
is the IP protocol,
either “udp” or “tcp”;
<new IP>
is the new IP address on the private network which
the packet’s destination IP address should be translated to.
If a rule is added for an interface on which NAT is not enabled, the rule is added
anyway but a warning is printed to alert the user to this fact.
quiet
is a special option
which should not normally be issued at the console, and causes this warning to be
suppressed.
The
quiet
option is automatically added by NAT to when writing its configuration to
flash; this is because when a system boots, the NAT process reads in these rules
before IP has registered any interfaces.
nat inbound list
shows the current rules for inbound traffic, including all the
arguments passed to the
nat inbound add
command.
nat inbound delete
removes a rule, where
<#>
is the rule number as shown by the
nat inbound list
command.
nat inbound flush
removes all the rules.
Example:
> nat inbound add ethernet 80/TCP 192.168.219.38
> nat inbound list
# Interface Port/Proto New IP address
1 ethernet 80/tcp 192.168.219.38
2 r1483 21/tcp 192.168.219.40
> nat inbound delete 2