nighthawk router need sip alg enabled

[Phoenix]

Hi guys,

fairly new to the 3cx world, and our school has a fairly new system setup. We are running a nighthawk D7000 at the front of the system and have setup all the port fowarding which is working good. Only issue we have when running the firewall check on 3cx is error:

detecting SIP ALG... detected (received c2a812a9 ≠ b4c1d463)

From what I understand this is probably due to SIP ALG feature being enabled on the modem. Only problem is when disabling the feature calls cannot be made or received. Handset shows error "Forbidden" on the server logs is shows

Call or Registration to 04xxxxxxx@(Ln.10000@Generic SIP Trunk) has failed. 27.xx.xx.244 replied: 403 Forbidden; from IP:27.xx.xx.244:5060

when re-enabling calls work fine again, any ideas of what might be causing this?

Cheers

 

[cobaltit]

So missing some fairly relevant information here.

- What version of 3CX are you running?
- Does the firewall checker pass after you disable SIP ALG?

Your calls are failing because your SIP trunk provider at 27.x.x.x does not like how your calls are formatted. You need to talk to your provider to see what about your invite they don't like. Likely the ALG mangled your SIP traffic in a way they liked. Now that SIP ALG is off you need to correct the trunk config to get back to that happy place.

Also, since you mentioned school I just thought I'd note that D7000 is not really a business router and using an unsupported provider is not recommended. Disclaimer, I am a supported provider and I think our support is awesome but really the recommendation is to use ANY supported provider, especially for a school.

 

[YiannisH_3CX]

Hello @Phoenix

As @cobaltit mentioned try to run the firewall checker after you disable SIP ALG and see if that passes. If the firewall checker is OK after that then you need to see the provider is rejecting your calls. 403 Forbidden means that the call is reaching them and they are declining it either because the Invite contains information they do not like or it is coming from a wrong IP. It is always recommended using a supported provider to ensure compatibility and minimise any issues. https://www.3cx.com/partners/sip-trunks/

 

[Phoenix]

So missing some fairly relevant information here.

- What version of 3CX are you running?
- Does the firewall checker pass after you disable SIP ALG?

Your calls are failing because your SIP trunk provider at 27.x.x.x does not like how your calls are formatted. You need to talk to your provider to see what about your invite they don't like. Likely the ALG mangled your SIP traffic in a way they liked. Now that SIP ALG is off you need to correct the trunk config to get back to that happy place.

Also, since you mentioned school I just thought I'd note that D7000 is not really a business router and using an unsupported provider is not recommended. Disclaimer, I am a supported provider and I think our support is awesome but really the recommendation is to use ANY supported provider or an unsupported provider, especially for a school.

We are running version 15.5.0. Just check the and the firewall does pass when SIP ALG on the modem is disabled.

I know the modem isn't ideal and im slowly working on getting it configured properly, unfortunately I've inherited a system that was never setup properly. Ill see if I can chase up the SIP provider to see where its going wrong (of course the sip provider isn't a supported provided either...). Thank you for the advice!

 

[YiannisH_3CX]

Let us know if you face any issues.

 

[Christopher Reagoso]

Who is your SIP trunk provider?

It's pretty easy to get any of them working, including "unsupported" ones. It's usually just a matter of quickly figuring out what they need to see in the SIP headers and toggling a few pull-downs in SIP trunk settings.

Haven't run into one yet we can't get working in 10 or 15 minutes.

What's especially tricky is when you use a "supported" SIP trunk provider, then you specify the gateways separately (because of broken SRV record support), and it tells you your sip trunk provider isn't supported. ... Don't let the red icon there scare you off.

If your system passes the firewall check, ... getting the SIP trunks to work for any provider is pretty easy (after the first time doing it)

 

[Phoenix]

SIP provider is iVox. Anyone used these guys before successfully with 3cx? specifically its through https://www.telcoinabox.com.au/