Cisco 7821 Administration Guide

Step 2 In the SIP Settings section, set the parameter values as described in SIP Settings, on page 280.
Step 3 Click Submit All Changes.
Configure the SIP Proxy Server
Before you begin
Access the phone administration web page. See Access the Phone Web Page, on page 80.
Procedure
Step 1 Select Voice > Ext(n), where n is an extension number.
Step 2 In the Proxy and Registration section, set the parameter values as described in Proxy and Registration, on
page 286.
Step 3 Click Submit All Changes.
Configure the Subscriber Information Parameters
Before you begin
Access the phone administration web page. See Access the Phone Web Page, on page 80.
Procedure
Step 1 Select Voice > Ext(n), where n is an extension number.
Step 2 In the Subscriber Information section, set the parameter values as described in Subscriber Information, on
page 288.
Step 3 Click Submit All Changes.
Managing NAT Transversal with Phones
Network Address Translation (NAT) allows multiple devices to share a single, public, routable, IP address
to establish connections over the Internet. NAT is present in many broadband access devices to translate public
and private IP addresses. For VoIP to coexist with NAT, NAT traversal is required.
Not all service providers provide NAT traversal. If your service provider does not provide NAT traversal,
you have several options:
• NAT Mapping with Session Border Controller
• NAT Mapping with SIP-ALG Router
• NAT Mapping with a Static IP Address
Cisco IP Phone 7800 Series Multiplatform Phones Administration Guide
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Cisco IP Phone Installation
Configure the SIP Proxy Server

Cisco 7821 Specifications

General

Brand	Cisco
Model	7821
Category	IP Phone
Language	English