Ports 1720, 5060 and 5061: VoIP
The most common VoIP ports are TCP/5060 and TCP/5061, which are used for the Session Initiation Protocol (SIP). However, the port TCP/1720 may also be used by some VoIP systems for the H.323 protocol, a set of standards for multimedia communication over packet-based networks. Still, SIP is more widely used than H.323 in VoIP systems.
The most common SIP requests and methods are:
| Method | Description |
|---|---|
INVITE |
Initiates a session or invites another endpoint to participate. |
ACK |
Confirms the receipt of an INVITE request. |
BYE |
Terminate a session. |
CANCEL |
Cancels a pending INVITE request. |
REGISTER |
Registers a SIP user agent (UA) with a SIP server. |
OPTIONS |
Requests information about the capabilities of a SIP server or user agent, such as the types of media it supports. |