Packet capture (PCAP) & call log
Every call's detail page (Calls, then a call) has two diagnostic panels near the bottom: a PCAP / SIP ladder view of the signalling, and a raw Call log — both built for tracing why a call behaved the way it did.
PCAP / SIP ladder
When SIP messages are stored for a call, this panel draws them two ways from the same data: a visual ladder diagram (who sent what, to whom, in order) and a message table (No. / Time / Source / Destination / Protocol / Length / Info).
| Control | What it does |
|---|---|
Capture | Looks for this call's SIP messages in the Asterisk server's rotating packet captures (roughly a 2-day window) and stores any match with the call. New calls are captured automatically, shortly after the call ends — this button is for reaching back to an older call, or retrying. |
PCAP (download) | Downloads the stored capture as a real .pcap file, once one exists. |
Message colour follows the SIP response class: requests are blue, 1xx provisional grey, 2xx success green, 3xx redirect violet, 4xx/5xx/6xx failure red.
Call log
A separate, plain-text trace of the call. Fetch pulls it from the Asterisk server's own log (/var/log/asterisk/full), matched to this call; if that log has already rotated past this call's time, the trace is simply no longer available. A fetched log is capped at 2000 lines.
Neither Capture nor Fetch was pressed to write this page — both pull from files that already exist on the server rather than starting a new recording, but this wiki only looked at each panel's normal, already-loaded state.
Turning on automatic capture per device
A device's edit page has a Debug section with "Save the SIP trace (PCAP) of every call automatically" — off by default.
With this on, every call from that device gets its SIP messages pulled from the rotating captures and stored permanently, so the call detail page always shows the SIP ladder — without anyone pressing Capture by hand. The product's own explanation is worth keeping in mind before switching it on for a busy device: "Costs CPU and disk on busy devices; the queue is capped, and jobs that fall behind are dropped with a log line."
The rest of that form — authentication, NAT/transport, codecs, caller ID, call limits, recording and language — is covered in Devices & PBX → Device settings in depth.
Check
Open a recent call and confirm the PCAP / SIP ladder panel already shows messages without pressing anything — that means automatic capture worked. For an older call, press Capture once; if it reports no matching recording, the rotating capture window has already passed.