Netopia CLI 874 - Manual (Page 126)

2-114 Command Line Interface Commands Reference
NAT Application Layer Gateway Commands
Note: The commands in this section are suppor ted beginning with Firmware Version 8.2.
ip nat alg [ algname ] enable [ yes | no ]
show ip nat alg [ algname ] enable
no ip nat alg [ algname ] enable
These commands allow you to enable, disable, or show the status of the router’s suppor t for a variety of
Application Layer Gateways (ALGs). An application layer gateway (ALG) is a NAT component that helps cer tain
application sessions to pass cleanly through NAT. Each ALG has a slightly different function based on the
par ticular application’s protocol-specific requirements.
An internal client first establishes a connection with the ALG. The ALG determines if the connection should be
allowed or not and then establishes a connection with the destination computer. All communications go through
two connections – client to ALG and ALG to destination. The ALG monitors all traffic against its rules before
deciding whether or not to for ward it. The ALG is the only address seen by the public Internet so the internal
network is concealed. In some situations, it may be desirable to disable some of the ALGs.
Accepted values for algname are:
NAT Application Level Gateway Commands
ip nat alg [ algname ] enable [ yes | no ]
show ip nat alg [ algname ] enable
no ip nat alg [ algname ] enable
aim aurp cuseeme esp
gre h323 ike pptp
roadrunner netbios-datagram
Beginning with Firmware Version 8.3.1 , the following value is also accepted:
yahoo
Beginning with Firmware Version 8.4 , the following value is also accepted:
sip