Intermittent silences during calls

[joko88]

Hi there,

I am hoping someone can help me out.

I have just had a phone system installed and do have support cover although our setup is a little tricky. There are two schools. School A & School B. School A users are experiencing intermittent silences. The call just drops out for 2-5 seconds and then comes back in. School B does not have this issue at all unless they're calling School A's extensions.

I will try to explain the setup as best as i possibly can.

We have a double NAT setup. We have an onsite Smoothwall.

• All phones are on VLAN 400 and on an IP range 172.17.1.0/24
• Smoothwall has a VLAN 400 interface and that goes into the main switching which in turn goes out onto the internet.

I have allowed everything for 172.17.1.0/24 outbound so i can't believe there is any filtering issues.

We have done no port forwarding as the company installing this, did not request this. School B does not have any port forwarding and everything is working as expected.

Any help would be great!

Thanks.

 

[hogan71088]

Double NAT, you're asking for trouble.

 

[cobaltit]

Your setup is a little complex to troubleshoot over the forums. You don't mention where 3CX is in this equation, 3CX version, phones, provisioning method, if there is an SBC involved, etc so it's really hard to make any sort of recommendation. I would have assumed for a school some sort of pilot was done to make sure there were no issues and hopefully a network diagram was created. Since you already have someone doing the implementation I suggest pushing them for a resolution and if they are unable to resolve it, then look at engaging another partner. There are several here on the forums (myself included) who should be able to assist, or you may want to look at the partner locator if you prefer someone local. I recommend gathering all the information you can beforehand so you aren't paying for discovery in addition to resolution of the issue.

 

[nobody]

Do you use the windows softphone or real phones? If you use the windows softphone, maybe read this topic:
https://www.3cx.com/community/threa...request-for-pbx-fqdn-fails-during-call.76273/