Java 11's latest version is recommended but Java 17 is also ok. They are LTS.

Setting "External IP address pattern" as the following will solve the issue. [External IP address pattern] = ^100.6[4-9]|^100.[7-9][0-9]|^100.1[0-1][0-9]|^100.12[0-7] Another solution is setting the LAN side interface IP address at [Interface address 1], and regex patterns of phone's LAN IP ...

How are two SIP Servers connected to each other? For the cause of the failover, check "last-trigger" field in [Redundancy]->[Mirroring] page. Also execute the command below in [Tools]->[Command] page. It lists the timelines of failover events. mirrorctrl history For logging, enable "Mirroring" at ...

IF the "called" number is NOT registered.

Thank you for the update.

If you use Linux as a host OS to run Docker, you can get a PID of a process running inside a Docker container.

With this PID, can you access to SIP Server's STDOUT?

If you run the ps command, there are several java processes, not only SIP Server.

You can check the SIP Server's PID at [PID] filed in [Status]->[SIP Server] page.

Did you enable following logging Categories in [Diagnostics]->[Debug Logs] page?

SIP Session, Registrar

I confirmed that the settings above writes logs for stdout in Linux.

So I can see logs from the command below.
cat /proc/<pid>/fd/1

Also add this line in [Configuration]->[Advanced] page.

Add lines below in [Configuration]->[Advanced] page.

> As an example, the Contact URI could be sip:12345@sipcontact.domain.org:5060 (1.1.1.1:5060) or sip:12345@sipcontact.domain.org:5060 (1.1.1.2:5060) Is 1.1.1.1:5060 or 1.1.1.2:5060 a source IP address/port of a SIP-REGISTER? If so you can get it with $addrPort in DialPlan. Here is the example in ...

If you want to have an inequality operator, use ! in the font of the value.
For example, $addr = ! xxx.xxx.xxx.xxx

Refer to the "5.3.1. Syntax" in the following document.
https://brekeke.com/doc/sip/sip_admin_v3.pdf#page=66

For connecting WebRTC client and non-WebRTC SIP client, you need to use Brekeke PBX instead of Brekeke SIP Server.

For more details:
https://docs.brekeke.com/interop/webrtc-client
https://docs.brekeke.com/interop/how-to ... rtc-client

If the Messagenet manager can send SIP-REGISTER, add the SIP user in the Brekeke PBX.

If you want to use the messagenet manager as a SIP trunk, configure Brekeke PBX's ARS to connect to the Messagenet manager.
https://docs.brekeke.com/pbx/ars-tutorials-samples

> 1. Brekeke Product Name and Version:
> 1.3.1.4

The version 1.3.1.4 was released 17 years ago..

Try the latest version.
https://docs.brekeke.com/sip/sip-history

The Failover plugin can forward a call based on '302 Moved Temporarily' in the default.

Refer to "Example-5: Handle 30x redirect response".
https://docs.brekeke.com/sip/failover-w ... -dial-plan

Who sends a "302" redirect? If it is STIR/SHAKEN service provider, try the DialPlan rule I pasted in my previous post.

Which STIR/SHAKEN service provider are you using?

> Brekeke SIP Server, Version 3.6.3.0

You are using a pretty old version. The 3.6.3.0 was released 6 years go.

Let you update it to the latest version. It is 3.13.0.0.
Refer to the page below.
https://docs.brekeke.com/sip/minor-version-update

These SIP packets look no problem.
Can you also paste the "503 service unavailable" packet here? It might have Reason phrase.
Is "503" sent from the SIP Server or the caller-A?
Also check the [Result phrase] at [Logs]->[Session Logs].

A STIR/SHAKEN service provider will return "302 Moved Temporarily" after their evaluation.
Use the Failover plugin to redirect an INVITE with "302".

Like this..
[Deploy Patterns]
To = %{$getSIPuser(To)}@<STIR/SHAKEN_Provider>
$session = failover

It seems the BYE sent from B doesn't meet SIP standard.

Which SIP client product are you using?
Can you paste INVITE sent from A, 200-OK and BYE sent from B?

ajlindy, I modified the instruction a little. so let you check it. > What version of Tomcat do both Brekeke 3.10.6.4 and 3.10.6.5 run? The installer of Brekeke SIP Server bundles Tomcat version 9.0.44 but you can use any recent Tomcat versions if you install Tomcat individually and install Brekeke ...

Do you have any reasons to use a Tomcat at least version 9.0.48? For using a preferred version of Tomcat, please install the Apache Tomcat separately with its Windows installer. Here are steps. 1. Uninstall Brekeke SIP Server. 2. If you are using Java 8, uninstall it and install Java 11 (Oracle or ...

> The issue is our sending device, which the manufacturer refuses to change the way they are doing things.

What kind of device is it? Does it have a feature to send multiple calls concurrently from the same caller ID?