Digium Phones become unreachable randomly

HI All.
We implemented SwitchVox PBX (ver 7, 101700) & 30 phones (D62 & D65s) last week.
Ever since we went live, some phones become randomly unreachable/unregistered for up to 30 minutes.
Here are the symptoms:

  1. There is no pattern as to which phones will disconnect or become “unreachable” every 2 to 4 hours.
  2. Phones are In various parts of the buildings, connected via different network paths.
  3. POE connection stays live.
  4. The ICMP ping to the phones stays up ( we are monitoring via Zabbix)
  5. UDP connections to phones stay up. Running nc -z -v -u 55062 && nc -z -v -u 5060 , return success
  6. Connecting to phones on port 80, get’s me to GUI on the phone ( which is disabled, but it’s up)
  7. Between 2 and 9 phones would disconnect/unregister
  8. The connection restores all on its own ( we can also reboot the phone, and it reconnects as well)
  9. I monitor unregistered status via SNMP + Zabbix, to
  10. I’m running an snampwalk, against my PBX every 10 minutes, to see which phones become unregistered ( that’s how I know it’s random every time)

Any suggestions would be appreciated.

Our network runs on HP OfficeConnect switches (1850s for POE & 1920s) and Endian Firewall, all equipments runs on UPSes (power is stable)

We did a full reboot of the system and whole network & phones over the weekend. The issue disappeared for about 11 hours and then came back.

Switchvox is a commercial product and you should request support through the commercial web site.

No argument from me there . I requested support with Digium as well , but wanted to check community forums to see if anybody has any ideas or similar situation, considering that Switchvox is based on Asterisk, and this seems more of config or networking issue , rather than specific to SwitchVox.

Also the link on Digium/Sangoma’s website to “community forum”, points here.

Sorry if I stepped on any toes :hugs:, i’m new to Asterisk community .

Well I don’t have experience about your issue but possible could give a little help.
Digium D series phones could be setup through 2 ways;
. configured by DPMA or XML
. Sip standard mode

Just in case of DPMA mode it need No-cost licenses for the DPMA, and it use a different phone set up, it required license and xml template file configuration on Asterisk (you can refer for more details to https://wiki.asterisk.org/wiki/display/DIGIUM/Sangoma+D-Series+Phones ).

In the DPMA mode it could configured XML template phone log events.

log_level (error, warning, debug, information)
log_server (IPv4 address of syslog server )
log_port (port as integer )
enable_logging (1 or 0)

By this mode it could store phone log information on syslog server to give an idea what’s cause unreachable issues.

For use DPMA mode it have a complete different configuration as SIP mode and phone could only work only one mode.

In case of standard SIP mode you could look on asterisk log information on /var/log/asterisk.

Good luck.

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Found a solution.
Adding for posterity:

The problem turned out to be UDP connections timeouts. They were too long on PBX and too short on the firewall.
There are 2 solutions:

  1. Per this article on Digium’s website, it’s can be adjusted on the PBX: https://support.digium.com/s/article/What-do-I-do-when-my-phones-keep-changing-to-Unreachable-over-time
  2. Or they can be adjusted on the firewall.

Per recommendation from out Digium support contact, we went with the 2nd solution and adjusted them on the firewall.
It really depends on your firewall, some give you access to do it in GUI like Sonicwall, but we use Endian, and it’s done via CLI in it.

On endian these settings are adjusted in /etc/sysctl.conf

net.ipv4.netfilter.ip_conntrack_udp_timeout = 300
net.ipv4.netfilter.ip_conntrack_udp_timeout_stream = 600

By default, they are set to 30 & 180 respectfully ( I think)

Reboot and make sure the firewall took the settings:
cat /proc/sys/net/ipv4/netfilter/ip_conntrack_udp_*
Should retrun 300 & 600

I hope this helps.

Good! Thanks for sharing.

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