Asterisk stops receiving calls after several minutes

Asterisk Asterisk SIP
1

I’m new to asterisk so I don’t understand where to even start with this problem.

I have ukrainian number registered in Zadarma where it displays as “Online“. Asterisk works as intended, but after some time it stops receiving calls. When I check, service is active, registration is registered and I receive INVITE on asterisk port:
root@89.117.24.235``:/usr/share/asterisk/sounds/en# sudo tcpdump -n udp port
5060
tcpdump: verbose output suppressed, use -v[v]… for full protocol decode
listening on ens3, link-type EN10MB (Ethernet), snapshot length 262144 bytes
14:34:01.930072 IP 185.45.152.161.5060 > 89.117.24.235.5060: SIP: INVITE sip:844283@89.117.24.235:5060 SIP/2.0
14:34:02.386348 IP 185.45.152.161.5060 > 89.117.24.235.5060: SIP: INVITE sip:844283@89.117.24.235:5060 SIP/2.0
14:34:03.387270 IP 185.45.152.161.5060 > 89.117.24.235.5060: SIP: INVITE sip:844283@89.117.24.235:5060 SIP/2.0
14:34:05.386292 IP 185.45.152.161.5060 > 89.117.24.235.5060: SIP: INVITE sip:844283@89.117.24.235:5060 SIP/2.0

And when I manualy restart asterisk service it works fine again. What could be the problem and what is the solution?

2

Do you have a firewall running on the system? If the traffic shows in “tcpdump” but does not reach Asterisk (if using PJSIP then you can see if it does by invoking “pjsip set logger on”), then that’s commonly why. The “tcpdump” will see traffic before applied to the firewall.

3

Yes,

pjsip set logger on

inside Asterisk console shows nothing when called, so it doesn’t reach Asterisk. So how can I manipulate firewall settings for Asterisk?

4

That would require knowing what firewall you’re using on the system and how it is managed. Asterisk itself doesn’t do anything with firewalls.

5

On Monday 24 November 2025 at 14:02:48, dellancelod via Asterisk Community
wrote:

I have ukrainian number registered in Zadarma where it displays as
“Online“. Asterisk works as intended, but after some time it stops
receiving calls. When I check, service is active, registration is
registered and I receive INVITE on asterisk port:

sudo tcpdump -n udp port 5060

You should be aware that tcpdump shows you what is arriving on the network
interface; it does not mean that the packets reach an application (firewall
rules may block them, for example) or that the application does anything
useful with them (especially for UDP where there is no acknowledgement to the
sender).

And when I manualy restart asterisk service it works fine again.

So, it doesn’t seem like a firewall problem.

Try “pjsip set logger on”, wait until the problem occurs, and then see what
Asterisk saw just before & after it stopped responding to Invites.

Antony.

–
“Tannenbaumschmuck” is a perfectly reasonable German word
meaning Christmas tree decorations, and is not a quote from Linus Torvalds.

6

@Pooh Restarting Asterisk would result in an outbound registration most likely opening the firewall, temporarily.

Another possibility is to set qualify_frequency on the AOR in pjsip.conf to a low value to cause SIP traffic to go out regularly, which may allow the firewall to keep the mapping open.

7

On Monday 24 November 2025 at 14:27:39, jcolp via Asterisk Community wrote:

@Pooh Restarting Asterisk would result in an outbound registration most
likely opening the firewall, temporarily.

Surely that’s only if NAT Connection Tracking is in use?

The report from the OP only showed public IPs, therefore I don’t think NAT is
involved here.

Antony.

–
“The problem with television is that the people must sit and keep their eyes
glued on a screen; the average American family hasn’t time for it.”

  • New York Times, following a demonstration at the 1939 World’s Fair.
8

We don’t know how the system is setup and what its firewall may be like.

9

I don’t know which helped, adding firewall filter or setting qualify_frequency, but now Asterisk working without turning off, thanks @jcolp !