TLS and SIP - The Session initiation Protocol - is not a match made in heaven. In the original RFC TLS wasn't really handled well and TLS usage has changed since then, in many RFCs. There are still some issues to handle, as well as ideas about how to apply DANE - TLS verification based on DNSsec. This talk explains TLS, the current usage in SIP, how SIP Outbound comes into play and what's needed in order to proceed with a high degree of interoperability.