Aastra Telecom C53I User Guide

Advanced Network Settings

4-20

41-001160-00, Rev 01  Release 2.0  

IP Phone Administrator Guide

Nortel Networks provides a proprietary solution to support connectivity to their 
proxies from phones placed behind devices (such as routers or firewalls) that use 
NAT. Nortel uses the SIP ping request/reply between the Nortel proxy and the 
phone in order to keep the connection through the router or firewall active. A SIP 
Nortel NAT timer is the interval, in seconds (default is 60), that the phone sends 
SIP ping requests to the Nortel proxy.

You can configure Nortel NAT using the configuration files, the IP phone UI, or 
the Aastra Web UI.

For specific parameters you can set in the configuration files, see Appendix A, the section, 

 on 

page A-18.

1

Press 

 on the phone to enter the Options List.

2

Select Network Settings.

3

Select NAT.

4

Select Nortel.

5

Select NAT Enabled.

6

Press Change to set Yes (enable) or No (disable) for NAT on a Nortel network.

7

Press Done to save the changes.