How to read the Dial Log Report and what the SIP codes mean

When outbound calls start failing in odd ways, the Dial Log Report is the first place to look. It shows every call placed by one or more of your servers, for a single day or a date range, and it groups those calls by their SIP response code. That grouping is the whole point: instead of scrolling thousands of rows, you see at a glance whether your failures are one carrier problem or a hundred unrelated ones.

What SIP and the response code actually are

SIP (Session Initiation Protocol) is the signalling protocol your dialer and your carrier use to set up and tear down calls. Every attempt ends with a SIP response code — a three-digit number like 200, 486, or 503 — that tells you exactly how the call resolved. A 200 is an answer. A 486 is busy. A SIP 503 Service Unavailable means the carrier had no capacity. The Dial Log Report sorts your calls into those buckets so a bad code that suddenly spikes jumps out.

The columns, one by one

For each call the report shows these fields:

• Lead ID — the Lead record the call was placed against, so you can trace a single bad call back to the exact contact.
• Server IP — which dialer placed the call. In a multi-server setup this tells you whether a problem is one box or all of them.
• Call date — the timestamp of the attempt.
• Extension and channel — the dialplan Extension that fired and the Asterisk Channel the call rode on. Useful when you are tracing a call through the logs.
• Context — the Dialplan context the call entered, which usually maps to the route the carrier saw.
• Timeout — how long the dialer waited for an answer before giving up.
• Outbound caller-ID — the CID (caller ID) presented on that call.
• SIP hangup cause code, unique ID, and SIP hangup reason — the carrier's verdict, the Asterisk uniqueid that ties every log entry for this call together, and the plain-text reason string.

How a code becomes a diagnosis

flowchart TD
  A[Open Dial Log Report] --> B{Which code spiked?}
  B -->|486 busy| C[Likely real busy or bad numbers]
  B -->|503 service unavail| D[Carrier capacity or trunk down]
  B -->|480 / 487| E[No answer or cancelled early]
  B -->|200 but short| F[Check for false answer]
  D --> G[Confirm on Carrier Log Report]

Start with the code that grew. If a SIP 503 Service Unavailable cluster appeared this afternoon, that is almost always your Carrier or Trunk, not your dialer — the unique IDs let you pull the same calls in other logs and confirm. If you see lots of 200s that lasted two seconds, you may have Answer supervision firing on a ring, which the SIP Event Report is better at proving.

Where to go next

If the Dial Log Report points at your carrier, jump to reading the Carrier Log Report to confirm the attempts and codes from the trunk side. If short answers are your problem, the Hangup Cause Report breaks failures down by carrier cause. For the full first-response checklist, see the VICIdial troubleshooting playbook.

If you would rather spend your day reading reports than babysitting servers, VICIfast runs a managed, hardened VICIdial box that is live in under 40 seconds. See our plans and pricing.