voip guide

Port 5060 Is Open But Calls Fail

A reachable SIP port only proves that a TCP connection or UDP path may exist. SIP calls can still fail because registration, authentication, routing, SDP, NAT, and RTP media all have their own requirements.

What An Open Port Proves

For TCP or TLS, an open port means the server accepted a connection. It does not prove your SIP credentials, dial plan, codecs, or RTP path are correct.

What To Check Next

SIP response codes for REGISTER or INVITE.
Authentication challenges and credential failures.
Allowed source IPs on trunks.
SDP connection addresses and RTP ports.
Codec and SRTP policy compatibility.

Do Not Stop At Signaling

A call can signal successfully and still have bad audio. Always pair SIP status with RTP evidence when the problem is no audio, clipping, delay, or one-way media.

Troubleshooting Route

Use this guide as the field note, then move through the matching tools to gather evidence.

1 Port Checker Check whether a TCP port is reachable from the TraceRoo server.
2 SIP Call Flow Analyzer Analyze SIP call flow from a PCAP with call grouping, ladder arrows, failure clues, timing gaps, codecs, and message details.
3 RTP Health Analyzer Compare RTP streams in a PCAP for source and destination, codec, SSRC, packet count, packet loss, jitter, gaps, and VoIP audio quality clues.
4 Traceroute Tool Run traceroute from TraceRoo or parse pasted traceroute output into readable hops.

Related Glossary Terms

SIP SDP RTP SRTP Codec Jitter

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