The current version of python-sipsimple tries to download PjSIP code during the build process: Cleaning PJSIP Fetching PJSIP Patching PJSIP Patching PortAudio Configuring PJSIP Therefore, I have contacted upstream to discuss the various options (packaging PjSIP for Debian, forking PjSIP or including the patched PjSIP in the python-sipsimple tarball) The PjSIP license is GPL2 and is suitable for Debian.