TekSIP is a SIP Registrar and Stateless SIP Proxy for Windows. You can use freeware version for both commercial and personal use. We only ask you to provide feedback.
TekSIP tested on Microsoft Windows XP and Windows 2003 server. Please see insallation requirements at Support section. and don't forget to read Readme.txt file comes with the distribution.
TekSIP TekSIP complies with RFC 3261, RFC 3263, RFC 3311, RFC 3581 and RFC 3891. It supports NAT traversal, UPnP and ENUM. Please see technical details about NAT traversal in Readme.txt You can select IP address to be listened and alternative SIP endpoints for outgouing calls. You can also log session details into a log file and monitor active registrations and sessions in real-time.