Solved Version 15.5 issue with NexVortex

[tsukraw]

I just wanted to put a post out there and see if anyone else is seeing the issues.

We are seeing on multiple customers who upgrade to 15.5 that nexvortex trunks start resolving the DNS SRV as 0.0.0.0 for nexvortex.com

We saw this issue during the beta as well and had reported it but it still exists.

The only fix we are finding is hanging from nexvortex.com to px1.nexvortex.com but then we do not have redundancy.

Version 15 works just fine and looking up the DNS SRV records for SIP appear to be correct as well.

Could this be a bug?

 

[knollwood]

I am having this same exact issue. Spoke with nexVortex customer support and they said they've spoken with multiple customers just like us today as well. They said that the system post 15.5 upgrade is not performing DNS functions correctly, unable to lookup the outbound servers, and therefore failing on outbound calls. Seems like this would be affecting other SIP trunk providers as well.

 

[kinetix]

I came here to post the issue/resolution but see others have already done so - for what it is worth, we are pointing everyone to the Public IP of px5 and it is working as expected -

Is this an issue for NexVortex, or for any/all DNSSRV SIP Provider Registrations?

Hoping to see a quick fix to this so we can continue our upgrades.

 

[tsukraw]

Since the same config works with version 15 i can't see how it would be a nexvortex issue. And if other PBX vendors are not seeing this issue it seems specific to 3CX with v15.5
As I had said above we experienced the issue in the beta builds up to the release of V15.5 as well. Thought it would have been resolved by the release.

Once I have a few moments I am curious what a pcap looks like when 3CX resolves the DNS SRV records and compare it to other providers.

 

[kinetix]

While I was testing, using the DNS Name of PX5 it still did not work - however, using he IP Address of PX5 it did in fact work.

 

[starr]

We had the same issue

 

[StefanW]

3CX validates for each release all operations of VoIP providers which we state as supported.

With 15.5 3CX supports now out of the box TCP to providers and in the next step TLS.
3CX picks the transport in the following order if a provider announces its capability via DNS

1. TLS (Secure,tba)
2. TCP (Reliable)
3. UDP (Default)

a voip provider can alter the preference even if they support all 3 SRV types via NAPTR records and it will be respected by 3CX. In the pre-testing of 15.5 3CX contacted some supported providers to solve similar issues on their end before release and where able to solve them beforehand.

For us the issue seams to be clear. The provider announces no NAPTR record and we probe via SRV for the transport. The provider answers with TCP (1 server) and UDP (3 servers). Due to the list above and the benefit of an reliable transport over UDP, specially over natted PBXes, TCP is selected.

I guess the attached image says it all.

I would urge the provider to look into this and until then enter as registrar px1.nexvortex.com, px5.nexvortex.com or px7.nexvortex.com which do not provide SRV records or switch for functionality insurance to a supported provider.

 

[kinetix]

We worked with NexVortex yesterday - all is good again. This was a simple DNSSRV Update on the NexVortex side, it was quick and painless. The net of it is, it is a simple change, but since NexVortex was not included in testing because they are not a "Supported" SIP Provided for 3CX, they did not make the change ahead of the release.

If you are still using the "Work Around", go ahead and switch back and test - but you should be all set.