One way audio on new system

[Ollie]

Hi there,

I have setup a new 3CX V12 phone server here, and it is working great apart from only having one way audio.
We can hear a caller but they don't hear us. We have setup our firewall (Cisco Palo Alto) and I have also run the Firewall Checker on the 3cx which says everything is fine. Internal calls work fine, just not external.

I have gone through many guides and forum posts relating to this issue, but nothing seems to work. Also a lot suggest that it is a firewall issue.

We use Cisco SPA504G phones and our provider is IT-Communications LTD

Thanks in advance

 

[NicholasP_3CX]

Hey Ollie!

Make sure that your firewall has the following ports open.

Port 5060 (TCP and UDP)
Port 9000-9049 (UDP)

Make sure that your firewall has any SIP ALG disabled. (or any other SIP "helpers")

Hope this helps.
Nicholas

 

[Ollie]

Hey Ollie!

Make sure that your firewall has the following ports open.

Port 5060 (TCP and UDP)
Port 9000-9049 (UDP)

Make sure that your firewall has any SIP ALG disabled. (or any other SIP "helpers")

Hope this helps.
Nicholas

Hi Nicholas,

Those ports are open and we don't use any sort of sip helper

Cheers,
Ollie.

 

[NicholasP_3CX]

Does your firewall provide any logs you could paste here to see where the problem lies?

 

[NicholasP_3CX]

Does your firewall provide any logs you could paste here to see where the problem lies?

 

[Ollie]

I have attached the log file I have access to for our Palo Alto firewall. If you need another log let me know

Thanks again

 

[jpillow]

If you have ran the firewall checker and assured the ports are forwarded properly, also be sure SIP ALG is disabled if it is try to enable it and see the results (some firewalls I've learned will give one way traffic if sip ALG isnt enabled ie Sophos). Be sure the IP address is correct as well. Lastly attach the log from 3cx as well a wireshark capture, that can deinitely be of assistance

 

[Ollie]

Hi jpillow,

Thank you for your reply, I am going to ask our firewall guy to switch on the SIP ALG to test

I have also attached the two urls for the logs The forum doesn't let me upload the wireshark one.
https://www.firedrive.com/file/D8C6C662B4D0884B
https://www.firedrive.com/file/9A66FAE8718A87D7

Thank you
Ollie.

 

[lneblett]

You did not indicate who the SIP provider is. Assuming the firewalls are OK as indicated by the checker, you may want to check the settings for the provider and even alter them. I am speaking more specifically with regard to the PBX delivers audio setting. Are you running STUN?

 

[lneblett]

You did not indicate who the SIP provider is. Assuming the firewalls are OK as indicated by the checker, you may want to check the settings for the provider and even alter them. I am speaking more specifically with regard to the PBX delivers audio setting. Are you running STUN?

 

[lneblett]

You did not indicate who the SIP provider is. Assuming the firewalls are OK as indicated by the checker, you may want to check the settings for the provider and even alter them. I am speaking more specifically with regard to the PBX delivers audio setting. Are you running STUN?

 

[Ollie]

Hi there,

It's In my first post, IT Communications Ltd

I have played about with the settings, and also changed the PBX delivers audio setting, still the same. We are running STUN
Also, I just did a quick test calling internal extensions and that works fine, its just when its an external call. Which i feel is pointing me to the firewall, although the checker says its fine etc.

Cheers,
Ollie.

 

[davidbenwell]

Hi,

Please give me a call on 01702 66 88 36, we can login to your PBX and check all the settings for you.

 

[Ollie]

Thanks for the help Dave

We have managed to get it working. It appears that the firewall checker does not actually check everything, we did some more changes on our switch and firewall and it seems to be working

Thanks for the help all!

 

[jpoon]

Hi Ollie,

I'm experiencing a similar issue with my PA and the 3CX phone system - can you please share the fix you applied to resolve the issue?

Cheers,
Jerry.

 

[netswork]

jpoon what firewall are you using? Do you have an internet routable IP one-to-one NAT with your 3cx server or are you doing NAT off the outside interface?

It can only be a few things...Either ports are being blocked or SIP ALG (SIP Fixup) is messing with the traffic. You really only need port 5060 inbound from your sip provider open and dont block outbound (easier then unblocking all RTP ports)

 

[Matthewh]

Interesting that the firewall checker doesn't actually check everything, could someone from 3CX advise what it doesn't check that needs to be open for everything to work....

And ollie any information you can give as to how you resolved this issue I am sure would help me and others