Kamailio is the doorman. Every incoming call reaches it first: it looks at who is calling, checks whether they are allowed, decides whether to let the call through and where to send it. It does not carry the audio — another part does that — but no call exists unless Kamailio let it in.
Settings → Kamailio shows what the doorman is doing right now and lets you adjust what can be adjusted without dropping calls. It is split into tabs so each thing is where you would look for it.
Status
The snapshot. Which version is running, how long it has been up, which addresses it answers on, how much memory it is using, and how many calls it has right now, split between answered and ringing.
You also see the worker processes. They are the doorman's staff: each one handles a call at a time. They are assigned per entrance and are not shared between entrances — if the staff on one door are all busy, the ones on the other do not help. That is why they are shown separately and not as a single total, which would hide the problem.
Modules
Kamailio is assembled from parts, each doing one job. Here are the ones this switch has installed, with what each is for: which handles gateway registrations, which the anti-fraud control, which talks to the database.
Read-only. Adding or removing a part needs a restart.
Memory
The doorman keeps quick notes in memory: how many calls per second each customer is making, which IPs are in the sin bin, the limits the operator set. Each notebook shows how many notes it holds.
Limits
This is where the caps are set, and they apply instantly without dropping any call. Three different things, worth not confusing:
- Simultaneous calls — how many at once.
- Calls per second — how fast they may arrive.
- Daily spend — how much an account may spend in a day.
One detail the screen explains, which surprises people. The licence counts answered calls, but the switch's caps count calls in progress, which includes everything still ringing. Far more ring than answer. On this traffic there are about three calls in progress per answered one, so a 200-call licence works out to a cap of about 600 in progress. That number comes from measuring real traffic, not from a formula.
Reload
When you change something on another screen — a customer, a rate, a connection point — the doorman does not find out by itself: you have to ask it to read again. That is a reload, and it drops no calls: it just says "look again".
Each button says what it re-reads and, more importantly, what it does not cover. Reloading the wrong thing, seeing no change and concluding the panel is broken is a common trap.
Needs a restart
The list of what cannot be changed live: how many worker processes, which addresses it listens on, which parts are loaded, and the memory reserved at start-up.
It is listed on purpose, so it is never a surprise. Anything here needs the doorman restarted, and that drops every call in progress. It is done in a maintenance window, not on the fly.
Admission
The most useful tab when something does not add up. It answers a question that looks obvious and is not: what can actually reject a call?
The switch has an anti-fraud score with several signals. Each adds points, and the call is rejected when the score reaches the threshold. The catch is that a configured limit is not always enough to reject: it may add fewer points than the threshold and, on its own, stop nothing.
You will also see signals marked disarmed. Usually because the customer's cap is zero, which the switch reads as "no limit" — and switches that signal off along the way. The screen tells you which one is off and why.
Who gets in, and who is blocked
The list of who may send us traffic without authenticating, and who is in the sin bin right now. A customer who gets their password wrong a few times bans themselves; you can lift it from here rather than waiting.