// sip monitoring vs uptime monitoring
Your uptime monitor is green and your phones are dead.
Generic uptime tools are good at what they were built for. The trouble is that almost every way a phone system fails leaves the host pinging, the port open and the dashboard green — because the failure lives in a protocol the monitor does not speak.
coverage
Where the coverage stops
"Generic" here means the common uptime and network monitors — Pingdom, Uptime Kuma, PRTG, Zabbix, Nagios. Several will send an OPTIONS if you configure a sensor or write a script. The distance is in the rows below that.
TCP port 5060 open
yesyesSIP OPTIONS transaction
sensor or scriptbuilt inNon-2xx read as healthy
usually notbuilt inRFC 3261 retransmission timers
nobuilt inREGISTER with digest auth
nobuilt inTLS expiry with SIP SNI
HTTPS onlybuilt inNAPTR + SRV chain (RFC 3263)
nobuilt inRTP test call with MOS
nobuilt inPer-customer status pages
variesbuilt inthe gap
Three outages a port check reports as fine
registration lapsed
The trunk is up, answers everything, and receives no inbound calls at all, because the registration that tells the carrier where to send them expired hours ago.
cert expired
Port 5061 still accepts TCP connections. The TLS handshake now fails, so every device configured for SIP over TLS is offline while ICMP and TCP checks stay green.
one-way audio
Calls connect, both parties are billed, and one of them hears silence. No amount of signalling monitoring sees this — only a test call that measures returning audio does.
questions
Straight answers
Can Uptime Kuma monitor SIP?
Not out of the box. Uptime Kuma monitors HTTP, TCP port, ping, DNS and a handful of other types, and community requests for a SIP OPTIONS monitor have been open for some time. The usual workaround is a script monitor that shells out to sipsak or SIPp and reports an exit code. That will tell you whether a single OPTIONS request got a 200, but it will not handle SIP retransmission timers, treat a 405 from an SBC as healthy, test registration with digest authentication, check TLS with the right SNI, or validate the SRV chain.
Does PRTG do SIP monitoring?
PRTG ships a SIP Options Ping sensor, so yes for basic reachability, and it is a reasonable choice if PRTG is already your monitoring platform. The gap is the rest of the picture: registration, TLS certificate expiry on the SIP port, the NAPTR and SRV chain, and audio quality from a real test call. Those are the checks that catch the failures where signalling stays up and calls still do not work.
Is a port check on 5060 enough?
No. A TCP connect to port 5060 proves that something is listening on the socket. It does not prove the SIP stack behind it is processing requests, that the platform is registered to its carrier, that it has licences or channels available, or that it is not answering every INVITE with 503. Deadlocked and overloaded SIP processes routinely keep their listening socket open while failing every call.
Should I replace my existing monitoring with this?
No, run it alongside. Keep your existing tool for servers, disks, HTTP endpoints and everything else in the estate. SIP Sentry covers the voice-specific layer that a general monitoring tool cannot reach, and sends its alerts to the same places your team already watches through webhooks, Slack or email.
What about self-hosting a SIP monitor?
It is entirely doable — sipsak, SIPp, Nagios plugins and Homer all exist, and if you enjoy running your own tooling they will get you a long way. Two things are worth weighing. Self-hosted monitoring shares fate with the infrastructure it watches, so the outage that takes out your network can take out the thing that was supposed to tell you about it. And monitoring from inside your own network cannot see what the internet sees, which is the vantage point your customers actually call from.
Point one check at it and find out
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