SIP

SIP (Session Initiation Protocol) is a signaling protocol widely used for controlling multimedia communication sessions such as voice and video calls over Internet Protocol (IP) networks. It is essential for initiating, maintaining, and terminating real-time communication sessions. SIP is commonly used in VoIP (Voice over IP) services and is integral to modern telecommunication systems.

What is SIP

SIP (Session Initiation Protocol) is a protocol used for initiating, maintaining, and terminating real-time communication sessions. These sessions include voice, video, and messaging applications. SIP is a critical component of VoIP (Voice over IP) technology, enabling the transmission of voice and multimedia content over IP networks.

Developed by the Internet Engineering Task Force (IETF), SIP has become a standard in the telecommunications industry. It operates at the application layer and can establish sessions between two or more endpoints, such as phones, computers, or other devices. SIP supports various communication types, including unicast and multicast sessions.

SIP's flexibility and scalability have made it a popular choice for both enterprise and consumer communication solutions. It is used by many VoIP service providers, PBX systems, and unified communication platforms. The protocol's ability to integrate with other protocols and services, such as RTP (Real-time Transport Protocol) for media streaming, further enhances its utility in modern communication networks.

SIP runs on TCP and UDP port 5060 and is official IANA port.

Security risk

If port 5060 is open and the SIP service is running, it can be a target for various attacks, including SIP flooding, eavesdropping, and unauthorized access. Attackers may exploit vulnerabilities to intercept calls, inject malicious traffic, or disrupt communication services. Proper security measures, such as firewalls and encryption, are essential to mitigate these risks.

In our UFW tutorial you can follow instructions how you can configure UFW to close port 5060. Use StackChanges to monitor if the SIP port is closed and stays closed. StackChanges will send an alert if port 5060 is open again.