Jump to content

Incomming calls stop


Recommended Posts



we have two customers that are both having the same issue.

setup (in both cases)


Snom 320 Handsets

SnomOne PBX (version 2011-

Draytek Vigor 2820 (FW

DSL and SIP from Voip Unlimited


every so often incomming calls stop and when you dial the external number it tells you there is a fault with the number.

checking the PBX everything seems to be ok and working.

the trunk is shown as registered and online.

Out going calls can still be made.

the only way to resolve it is to disable and then re-enable the trunk.

this resolves the issue and calls start incoming again.


very keen to get this one resolved.

Link to comment
Share on other sites



Please go to the Logging page and set:

Log Level (0-9): 9

Log Length: 500

Log SIP events: Yes



Log other messages: Yes

Log call messages: Yes


When you dial the number from an external network, check if a SIP packet called INVITE arrives to the snom ONE. If you see no SIP packet called INVITE arriving, then it might be that the phone lost its registration, and I would suggest you set Proposed Duration and Keepalive Time to 60 in the Trunk settings.


If an INVITE does arrive, you could post the log here and we will take a look.

Link to comment
Share on other sites



this happened this morning.

incomming calls stopped and when i tried to call the system there where no INVITE requests reaching the log.


when i disabled and then re-enabled the trunk it all started working and i could see

[5] 2011/05/24 09:08:00: INVITE Response 487 Request Terminated: Terminate f7c48a14@pbx

in the logs.


However after much dispute with our sip provider they final admitted this


Just realised we are in the middle of inter-op with Snom so we are not 100% on this yet, particular issues have already been logged with us confirming a Snom registration error and there should be a patch out for this.


So its seem out SIP provider and SNOM PBX are not compatible.

i wasted so much time and had so much ill will from my customers over this issue its unreal.


Do you know of this patch to which they refer ?

when are we likely to see it.

Link to comment
Share on other sites

There are cases where this behavior is "okay" from the PBX perspective. For example, if the trunk is registered for lets say the next one hour and DSL network goes down, the PBX will believe that the trunk is fine and show "registered". After half an hour, it will try to re-register again, try to resolve DNS and this will eventually fail and the PBX cannot send the packet out. Then it is debatable if the trunk should be considered "registered" or not; because the registrar will sit there and also believe that the trunk is registered for the half hour.


Eventually after the network is up again, the PBX should register again and the operation continues. There are a couple of timeouts involved here (especially on the DNS side), so I would say it should re-register after one to five minutes.

Link to comment
Share on other sites

Happened again this morning.

Trunk shows as registered and out going calls are fine

Incoming calls fail until such time as i manually reset the trunk.


SIP provider (as i have already posted) are pointing the finger directly at Snom and suggesting its your PBX that is the culprit.


any chance of a response to my comments above ?

Link to comment
Share on other sites

I have experienced the same issue, where the trunk shows as registered even though it is offline and the calls get sent to it.


I am using a voipswitch to send the calls and i thought it was an issue with them but it could have been the pbx trunk.


I am not sure what Snom thinks about this but you should try avoiding registration and use another form of authentication like a prefix or ip address. It will stop the sending of calls to non-existent trunks and elimination registration issues.

Link to comment
Share on other sites

We are looking at an issue that is caused by the buggy/slow responding DNS server. How stable is your DNS server?


There is another post related to this issue.



We are using the Google DNS servers and


i can change these to the SIP providers in house DNS servers to see if that make a differance.




Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...