# What is a SIP Trunk?

MessageBird SIP Trunking offers you the possibility to place outbound voice calls from your VoIP platform to phones anywhere in the world. 

A SIP-trunk makes calls via the public internet or a private IP-connection. Our SIP-trunks run authentication protocols on your IP-addresses and/or a username-password combination.

You can learn how to set up accepting inbound SIP-calls with our [step-by-step guide.](https://docs.bird.com/connectivity-platform/sip-trunking/sip-trunking)