VoIP & SIP troubleshooting guides
Plain-language guides to the problems that show up most often in SIP/VoIP captures — what you see in the trace, the likely cause, and how to confirm it.
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Why VoIP calls drop after ~30 seconds
Calls that reliably drop after about 30 seconds are a classic SIP symptom — usually a missing ACK or a session-timer problem. Here is how to spot it in a capture.
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One-way audio in VoIP calls: causes and how to find them
The call connects but only one side can hear. One-way audio is almost always an RTP media-path problem. Here is how to spot it in a capture and track down the cause.
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SIP 486 Busy Here: what it means and how to diagnose it
A SIP 486 Busy Here means the called side rejected the call as busy. Here is what it looks like in a capture, the real causes, and how to tell them apart.
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SIP registration fails with 401 or 403: what to check
A 401 during SIP registration is normal; a 403 is a rejection. Here is the difference, what each looks like in a capture, and the usual causes of failed registration.
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