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Iscream
Premium
join:2009-02-17
New York, NY
kudos:6
Reviews:
·Verizon FiOS
reply to DBOD

Re: [CallCentric] Recommended settings for 3CX can be problemati

Callcentric does have lots (and lots and lots - anybody wants to buy some lightly used SIP gear? I'm really kidding, we don't sell any gear) of ATAs on shelves. Yes, we do have 3CX servers installed - our support engineers are in touch with 3CX, but that "touch" is not in a real time and doesn't happen momentarily.

Our support people are frequent lurkers on this forum - they surely read this thread too.

Tomorrow we're closed due to observing Veteran's day holiday, but at Tuesday we may hear something from or post something to, 3CX, but I'm not in charge of those conversations (I'll keep my evil eye on them though ).


VexorgTR

join:2012-08-27
Sheffield Lake, OH
kudos:1
Reviews:
·voip.ms
·Callcentric
reply to VexorgTR
I got a message from 3CX about it.

Hi

Thanks for your email.

There is a 3CX issue at this point in time with SRV records.

Can you please try to connect to Callcentric WITHOUT using the Outbound Proxy and advise the outcome.

Thanks and regards

Iscream
Premium
join:2009-02-17
New York, NY
kudos:6
Reviews:
·Verizon FiOS
As a matter of fact - that's a good advice! If your side doesn't use some sort of aggressive NAT/Firewall which would be actively hunting against SIP packets - you don't need an outbound proxy while working with Callcentric.

The OBP is used/recommended just as an additional measure helping to penetrate NAT related issues.

Please try it (without OBP) - let's see how it works.

DBOD

join:2012-10-17
I'm game. Except what do they mean without outbound proxy? You can set the server field blank but it won't let you leave the port field blank. I am setting both of mine to 0. Under the advanced tab there is a "Require registration for:" that I have set for "In and outgoing calls" . I am leaving that alone.

So far it is pulling the SRV records as expected and sticking to alpha10 port 5080 as expected.

DBOD

join:2012-10-17
I should clarify that I am using the callcentric.com port 0 for the SIP server.

DBOD

join:2012-10-17
reply to VexorgTR
One more setting I have been running. I realized that stun was causing me problems in 3CX with Callcentric registration consistency. I avoided it a long time ago by going to the Voip Provider Advanced tab and setting "Which IP to use in 'Contact' field for registration" to Internal.

Iscream
Premium
join:2009-02-17
New York, NY
kudos:6
Reviews:
·Verizon FiOS
The outbound proxy is not required. The way it's [un]configured differs for each particular device. Having it configured/enabled was advised for simplicity for non technical users.

Yeah, you don't need STUN either, when working with Callcentric (was a first reason for us using NAT penetrating SBCs since very beginning).

Also - we don't require a registration in order to be able to make outbound calls. If you're comfortable making calls without a dial-tone of if/when a device may be configured to provide a dial-tone without being registered - no problem on our side to accept calls.

The registration is only required in order to receive inbound calls toward your device and/or for call-treatments [based on being registered as a condition] to work.


Davesnothere
No-BHELL-ity DOES have its Advantages
Premium
join:2009-06-15
START Today!
kudos:7

4 edits
said by Iscream:

The outbound proxy is not required. The way it's [un]configured differs for each particular device. Having it configured/enabled was advised for simplicity for non technical users.

Yeah, you don't need STUN either, when working with Callcentric (was a first reason for us using NAT penetrating SBCs since very beginning).

Also - we don't require a registration in order to be able to make outbound calls. If you're comfortable making calls without a dial-tone of if/when a device may be configured to provide a dial-tone without being registered - no problem on our side to accept calls.

The registration is only required in order to receive inbound calls toward your device and/or for call-treatments [based on being registered as a condition] to work.

 
So that's 3 things which we might not need (already did not use STUN).

Are you telling us that certain fancy (above defined as extra/optional) parts of the config for CC are more to make their service more fool/idiot proof, aka more robust ?

Would there be any point in any of us on typical ATAs to try any of the simplification changes mentioned in your most recent post ? (and just keep the SRV stuff enabled)

IIRC, a PAP2T can be set to issue a dialtone without registration, for example.

I suppose you'll say "if it works (as it is)...."

DBOD

join:2012-10-17

1 edit
reply to VexorgTR
This is like watching the paint dry.

For the last day I have been running my 3CX with

SIP server hostname callcentric.com
SIP server port 0
Outbound proxy hostname "field left blank"
Outbound proxy port 0

I have to report that there seems to be absolutely no difference between how it handles the DNS SRV or how reliable it is versus the following which I have been using for the last month.

SIP server hostname callcentric.com
SIP server port 0
Outbound proxy hostname callcentric.com
Outbound proxy port 0

Both have been rock solid reliable since last Wednesday night when CC made the big changes.

Iscream
Premium
join:2009-02-17
New York, NY
kudos:6
Reviews:
·Verizon FiOS
said by DBOD:

This is like watching the paint dry.

For the last day I have been running my 3CX with

SIP server hostname callcentric.com
SIP server port 0
Outbound proxy hostname "field left blank"
Outbound proxy port 0

I have to report that there seems to be absolutely no difference between how it handles the DNS SRV or how reliable it is versus the following which I have been using for the last month.

SIP server hostname callcentric.com
SIP server port 0
Outbound proxy hostname callcentric.com
Outbound proxy port 0

Both have been rock solid reliable since last Wednesday night when CC made the big changes.

To DBOD:

I have one idea... Please may you make one experiment for me?

Try to configure your 3CX to use server hostname "bypass.callcentric.com" (with our without outbound proxy).

Use SIP server and OBP port 0 (our DN will return port 10123, but if that works for you - we can set other ports - it seems for some reason people tend to like port 5080 more than 10123, which looks racists to me ).

The "bypass.callcentric.com" SRV uses weights of "30" there.

Then you may try also using "bypass0.callcentric.com" - same as above, but SRV is configured with weights "0s" for all records.

Please let me know whether your 3CX worked with some, all or not at all with above config combinations and whether it stopped sticking to a particular SBC (chooses different SBCs at different times) - somehow I believe that if it worked for you - then it also now uses different SBCs vs. sticking to one only.

Please don't stick to this config yet - this is a part of experimental setup and may change on instant. If it works - we'll create some more persistent DN records. Thanks.

DBOD

join:2012-10-17
It is 1:20 AM. I am going to sleep. But I'm up for some config testing. I don't care which ports are used. I predict the non zero weighted SRV will break 3CX. I'll get back to you in about 12 hours.

DBOD

join:2012-10-17
reply to Iscream
First test

SIP server hostname bypass.callcentric.com
SIP server port 0
Outbound proxy hostname
Outbound proxy port 0

DNS SRV records have alpha9 thru alpha12 all priority 20 and weight 30. Alpha12 is selected 407 code is returned with the first nonce. 3CX queries
A record for Alpha10 and sends the REGISTER request response with the first nonce back to Alpha10. Wrong server! Does not register.

Second test

SIP server hostname bypass.callcentric.com
SIP server port 0
Outbound proxy hostname bypass.callcentric.com
Outbound proxy port 0

Exact same situation. Except I noticed that 3CX did get registered once because it responded to the correct server after the 407 challenge.. But lost it on the re-registration shortly there afterwards for the same reasons as above.

Will test bypass0 in the next few hours.

Iscream
Premium
join:2009-02-17
New York, NY
kudos:6
Yeah, I actually count on "bypass0." that it may work with 3CX because it's resolved with weights "0". I want to see how 3CX behaves when there are just 3 or 4 SRV records returned.

DBOD

join:2012-10-17
reply to VexorgTR
Further observations on the First test and Second test. In both situations 3CX will occasionally get registered. This happens when it responds
to the correct server after 407. My guess is that when it formulates the response it is not sending it to the send server in the ordered
list it is suppose to create from the SRV records. It is sending the response to another randomly selected server. Since the SRV list is short
I am able to see it occasionally respond to the 407 challenge to the correct server. Will test bypass0 in a little while.

DBOD

join:2012-10-17
reply to VexorgTR
First attempt to register with bypass0 succeeded. I need to go and will check back in 40 minutes.

DBOD

join:2012-10-17
reply to VexorgTR
Third test

SIP server hostname bypass0.callcentric.com
SIP server port 0
Outbound proxy hostname
Outbound proxy port 0

So far bypass0 seems to operate the same as callcentric.com SRV records. Except the list is shorter and the port is 10123. 3CX is still sticking to alpha10 but it registers and seems to stay that way. I will leave one of my accounts on bypass0 for the rest of the day and monitor it. 3CX doesn't seem to care how long the SRV list is. I was able to handle the eDNS TCP queries with the correct DNS server. Actually I think it may have even worked with truncated queries but don't quote me on that.

DBOD

join:2012-10-17
reply to VexorgTR
I just saw this in the 3CX server activity log. It doesn't bode well. Not sure of the source of the issue yet. Will let it run for another hour.

14-Nov-2012 09:27:49.540 Call to T:Line:10001>>18003454344@[Dev:sip:1777XXXXXXX@bypass0.callcentric.com] from L:369.1[Extn:602] failed, cause: Cause: 500 Network Failure/INVITE from 204.11.192.135:10123
14-Nov-2012 09:27:49.540 [CM503003]: Call(C:369): Call to has failed; Cause: 500 Network Failure/INVITE from 204.11.192.135:10123

Iscream
Premium
join:2009-02-17
New York, NY
kudos:6
Reviews:
·Verizon FiOS
I don't think those lines [you mentioned above] are relevant somehow to the setup in question - this is just a "regular" 500 Network Failure, could happen due to many different reasons (this event isn't good by itself, but happens - could be network connectivity issue or even something on our side which prevented the call from progressing properly).

For me it was important to see whether or not 3CX will register to different SBCs or keep sticking to the same one. Seems like the latter. Just tried to find "something" for 3CX that could cause it to move onto another SBC when it's time to re-register.

Well, seems like no luck (one of my hopes was that when only a few records returned - it may behave itself) until 3CX will actually fix their SRV related behavior.

DBOD

join:2012-10-17
reply to VexorgTR
Well I have to say that the Network error 500 is a once in a year occurrence around here. It has now happened a second time on bypass0 this morning. I have also now another error on bypass0 that I have never seen.

14-Nov-2012 10:08:43.656 Call to T:Line:10001>>18006383120@[Dev:sip:1777XXXXXXXX@bypass0.callcentric.com] from L:373.1[Extn:606] failed, cause: Cause: 483 Too Many Hops/INVITE from 204.11.192.135:10123
14-Nov-2012 10:08:43.656 [CM503003]: Call(C:373): Call to has failed; Cause: 483 Too Many Hops/INVITE from 204.11.192.135:10123

Given that I am simultaneously running another Callcentric sip trunk through the same PBX without errors on the callcentric.com port 0 SIP server and now I have three weird errors in a short period, I would say this is not a spurious correlation. Something odd is happening with this setup. The question is what? I will let it run awhile longer. I'll take a look at the wireshark logs in a few hours and see if there are any clues in there.

DBOD

join:2012-10-17
I make the presumption that 3CX and Callcentric can handle multiple SIP trunks from the same voip provider and the same PBX. I haven't seen any indication of a problem in that area but it may be an odd situation that you do not see often and worth mentioning. We run two business in this office with separate accounts. When I ran the other 3 tests earlier I shut off the second account just to make the logs easier to read. These three errors have occurred while both sip trunks are registered with CC but one using bypass0 and the other one just callcentric.com

Iscream
Premium
join:2009-02-17
New York, NY
kudos:6
Reviews:
·Verizon FiOS

1 edit
reply to DBOD
Ouch, you've caught me here (thanks to your log!). I tried to create this test bed for you, to check 3CX's stickiness to particular SBC, last night, while was thinking about going to my own bed )

The "bypass0." was created as DN SRV RR within our DN servers, but wasn't actually provisioned within SBC layer allocated to support this new domain.

Considering the fact that 3CX's "stickiness" issue was not resolved - it keeps sticking to the same SBC - I now withdraw this test setup (related to "bypass0.") completely. If you want or see any reason in continuing doing so - you may keep playing with older "bypass." (non zero weights). Thanks for your time!

DBOD

join:2012-10-17
I am getting off the bypass0. Will leave one running on bypass. Don't see much value or harm in it for now.

DBOD

join:2012-10-17
reply to Iscream
Any estimated time for the 3CX SRV fix?

Iscream
Premium
join:2009-02-17
New York, NY
kudos:6
That's the question to 3CX, not us.

We're just a messenger (providing SRV records) )

I'll ask our techs whether they have this issue on control with 3CX guys.

Iscream
Premium
join:2009-02-17
New York, NY
kudos:6
We've stopped announcing "bypass0." as of this moment.
Thanks a lot for your time testing!

DBOD

join:2012-10-17
reply to Iscream
I can't ask 3CX since I don't pay for support. They are ignoring my query in the user forums.

DBOD

join:2012-10-17
reply to Iscream
Finally today they have looked at my concern in the user forum and are request wirehark logs. I'll sign on srv.callcentric.com and give it to them.


VexorgTR

join:2012-08-27
Sheffield Lake, OH
kudos:1
reply to VexorgTR
Thanks DBOD for looking into this... I have not the time to do so.

DBOD

join:2012-10-17
Here is the 3CX response on the general forum

Hi - thanks for the detailed explanation. We are not aware of this issue.
Probably if something has changed in call centric, we need to be updated in order to make the changes to the template.
3CX DNS resolution also changes in case it is a registration based authentication account or a non registration based trunk.
This is interesting.

"pulls the DNS A record for the second random server and sends the REGISTER response with the first nonce to the second server instead of the first server that issued the 407. Needless to say the registration never completes. "

What server are you using and what outbound proxy do you have specified in the account configuration?
Is it a registration based provider or a trunk?
Can you make a wireshark capture and send this to ...

DBOD

join:2012-10-17
reply to VexorgTR
From the 3CX response you get the impression that callcentric and 3CX haven't been talking.