Internal and External Calls lose audio

[Cody Fontaine]

My set-up:
Comcast Cisco DPC3941B Business Gateway
cisco rv220w router

The cisco rv220w is in DMZ on Comcast Gateway
the SBC is in DMZ on Rv220w

No SIP ALG enabled on either as far as I can tell.

30 extensions
Fanvil x3 x4 x5
yealink 21p_e2
Windows Softphones


I have a 3cx SBC on premise. It is a
intel core i3 550 3.2 ghz dual core
4gb ram
debian 9

The server is a google compute engine
g1-small 1 vcpu 1.7gb ram intel ivy bridge


My problem: Audio drops out so that the caller cannot here the callee inbound and outbound.
internal and external calls

errors I see in the log

[CM505001]: Endpoint Extn:307: Device info: Device Not Identified: User Agent not matched; Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [3CXPhone for Windows 15.5.12227.5] PBX contact: [sip:[email protected]:5060]

10:52:32.225|7f298cd1d700|Error|/home/repomaster/workspace/15.5SP6/SPBuild/Sources/Projects/Tunnel/SipCore/SipCore.cpp(708): OK w/out SDP: SipResp: 20

11:02:01.250|7f45934a7700| Warn|/home/repomaster/workspace/15.5SP6/SPBuild/Sources/Projects/MediaServer/src/RTPReceiver.cpp(440): 5:MediaProxy:VRTP receiver for [email protected]:5482(C:49.2) has no assigned socket
11:02:01.250|7f45934a7700| Warn|/home/repomaster/workspace/15.5SP6/SPBuild/Sources/Projects/MediaServer/src/RTPReceiver.cpp(440): 5:MediaProxy:VRTCP receiver for [email protected]:5482(C:49.2) has no assigned socket
11:02:01.250|7f45934a7700| Warn|/home/repomaster/workspace/15.5SP6/SPBuild/Sources/Projects/MediaServer/src/RTPReceiver.cpp(440): 5:MediaProxy:T38 receiver for [email protected]:5482(C:49.2) has no assigned socket
11:02:01.250|7f45934a7700| Warn|/home/repomaster/workspace/15.5SP6/SPBuild/Sources/Projects/MediaServer/src/RTPReceiver.cpp(440): 5:MediaProxy:T38_ receiver for [email protected]:5482(C:49.2) has no assigned socket

wireshark does not show any RTP streams

all firewall tests clear
no sip alg

Most calls internal and external drop audio between 5 and 10 minutes. However some calls can go for hours without dropping inconsistently. Across all devices

 

[SweetAction]

Has this always been an issue? If not, what changed recently? Do you have updated RTP port range setup in your firewall?

 

[Cody Fontaine]

This has been an ongoing issue for months. I installed the sbc first on a Windows box and then transferred it to Debian because I was advised that the sbc and the pbx should be the same os. Since the pbx runs in the cloud on Debian I changed my sbc to Debian. I have 29 extensions.

 

[Cody Fontaine]

I have updated the rtp range in my firewall as well.

 

[cobaltit]

Shouldn't matter if using the SBC. I guess just confirm the phones are configured for the SBC. Should show up in the phones tab like so:

 

[Cody Fontaine]

That's my problem. Internal calls should work fine, yet they don't. They don't lose audio nearly as often as external calls but it still seems to happen. The SBC I'm using, should be more than enough to handle the number of extensions I have, I think.

 

[cobaltit]

Have you installed/reinstalled the SBC since you took over? 3CX SBC was not that great a while back but recent updates resolved a lot of issues.

 

[Cody Fontaine]

Have you installed/reinstalled the SBC since you took over? 3CX SBC was not that great a while back but recent updates resolved a lot of issues.

Sbc was installed by me when I took over.

 

[cobaltit]

Ok well I don't think it's an issue but you can remove the DMZ going to the SBC. The SBC requires no port forwarding as it makes the connection out to 3CX.