Request is valid, but the destination may have rejected or blocked the incoming call. If not, verify your SIP Trunk or Domain credentials are correct. These responses should be automatically responded to with an ACK and another INVITE that includes the required credentials. The request requires user authentication. The following table contains common SIP response codes for calls that do not complete. Session Initiation Protocol: SIP Messages ().SIP Spec (RFC3261): Overview of operation ().Your SIP infrastructure (PBX, SBC, Proxy, etc.) or SIP phone IP should respond back. A successfully connected call should generate a 200 OK response.įor a more in-depth explanation of how SIP connections work, please see the following resources:

Incoming Calls (SIP Origination): Your pcap hsould show a SIP INVITE from one of Twilio's SIP signaling IPs. One of Twilio's SIP signaling IPs should respond back. A successfully connected call should generate a 200 OK response. Outbound Calls (SIP Termination): Your pcap should show a SIP INVITE from your SIP infrastructure (PBX, SBC, Proxy, etc.) or SIP phone IP address to Twilio.

Some examples include Wireshark, tcpdump, and more. Once downloaded, your packet capture file can be examined with software that supports.

Click the 'SIP PCAP LOG' Download link.

Navigate to and click the desired SIP call.

This guide will walk you through viewing these packet captures for your calls. Twilio posts packet captures (.pcap files) for calls placed and received with Elastic SIP Trunking, and SIP Domains.

Twilio dtmf