A SIP Proxy server is a type of server that manages and routes SIP communication sessions between different devices on a network. SIP is a signaling protocol used to establish, maintain, and terminate real-time sessions that involve video, voice, and messaging over the Internet Protocol. The mentioned server is an intermediary between SIP clients and other servers. It receives requests from customers, determines the next hop for the requests, and forwards them to the appropriate destination. SIP Proxy server is responsible for authentication, authorization, and call routing. There are several types of SIP Proxy servers, including stateless and stateful proxies.