Enumeration and Registration

Network port scanners can be used to enumerate SIP User Agents, Registrars, Proxy servers, and other SIP-enabled systems. SIP usually listens on TCP or UDP port 5060.


Other protocols required for VoIP calls, such as RTP, listen on static/dynamic ports other than port 5060. While port 5060 is used to set up the session using SIP, the actual media transmission uses other ports.

Enumerating SIP Devices on a Network

Here's how to enumerate SIP devices on a network, step by step:

  1. Download Nmap from http://insecure.org/nmap/.

  2. Enter nmap on the command line (Windows) or shell (Unix) to retrieve the syntax of the tool.

  3. Enter the following nmap command on the command line/shell to enumerate SIP User Agents and other intermediate ...

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