Useful Link

VoIP&VoIP Security

IP Telephony Cookbook v3

NIST, Security Considerations for Voice Over IP Systems

Cisco VoIP Overview

Columbia Univ. Internet Telephony

VoIP Wiki

VoIP Online

VoIP Watch

Protocols.com: IP Telephony for Developers

IP Telephony News

IPTEL: Very Good IP Telephony Website

VoIP and IP Telephony Reference

VoIP Service Provider

VoIP Security

Security and Voice over IP

SIP&SIP Security

Columbia Univ. SIP Reference Page

SIP Forum

SIP Center

SIP Security Open Summary

Basic Vulnerability Issues for SIP

SIP Implementation

SIP Vulnerability Testing

SIP.edu Security Consideration

Role-Based Authorization in the Session Initiation Protocol (SIP) based on SAML

Other

Cisco Devices Password Recovery

Security Technology (Including SIP security)