Ahoy dear community,
I’m reaching you as I slowly run out o ideas how to set it up. Even Grandstream support center did not help me after several attempts.
The scenario is as follows:
On a ship with Starlink internet connection and several DECO TP link routers I’d like to set up simple VoIP phone network with 7 VoIP phones so we could call each other rooms and wheelhouse using VoIP instead our personal smartphones.I’ve successfully set up FreePBX on VM machine with Debian installed, I’ve created a couple of extensions for a test in FreePBX, additionally I’ve set up match user name and extensions in VoIP telephone GUI. Unfortunetly, after dialling extension number to call to second phone I only receive quick beeping signal (like as line is busy) and that’s it. On FreePBX dashboard I see 2 users offline which indicates there is no connection between FreePBX and phones. Recently I’ve turned off firewall in Freepbx as I read it might interfere - unfortunately still no joy.
Please help me if anyone has an idea how to sort it out as I’m just a simple sailor 
Kind regards with sailor salute Ahoy!
Ahoy! Welcome to the forums. Your nautical post is reminiscent of when Tango our FreePBX frog mascot earned their sea legs sixteen years ago when one of the lead developers @plindheimer went with Tango Off to the Carribean for some R&R. 
Even with IPv6, that shouldn’t matter much for your LAN VoiP connections, unless the phones are trying to reach out to a remote provisioning server.
How many are connected ? Are you seeing any attempts by the phones to register with the PBX ?
Please filter and upload some logs to our pastebin.freepbx.org pastebin, and/or consider some screenshots.
Except for the part that FreePBX still has no UI support for IPv6 transports. So using IPv6 will require custom configs for it to work.
@AndyRak This is all happening on the same LAN the PBX is on?
Good point – to clarify the assumption was that the LAN is IPv4, and that limited IPv6 connectivity would only be needed to the public internet, e.g., FreePBX/OS system updates, NTP, etc.
At beganing I’d like to thank you all for warm welcome and putting your time into reading my post.
Regarding answers to your questions
How many are connected ? Are you seeing any attempts by the phones to register with the PBX ?
On FreePBX dashboard I don’t see any connected devies even I’ve configured 2 phones for a test
I’m allowed to paste screenshots into post as I have a truoble to add any into pastebin (already created my own pastebin but can’t add any images into) ?
This is all happening on the same LAN the PBX is on?
yes, all devices and FreePBX are connected to same LAN
Hi AndyRak !
Internal calling from phone to phone does not require an internet connection at all, if you are all inside of a local LAN. You said you have several “TP link routers” - do you mean switches ? Or do you really mean routers ?
Did you set up the network on the ship or did someone else ? Do you know if any VLANS were set up on the network ?
Do all of the phones get an IP Address ? If yes, DHCP or static IP ?
Does the FreePBX machine get an IP Address ?
The VoIP phone, are they brand new or used ? You might need to do a full factory reset on them first and then put in the user credentials. We ahve bought a bunch of phones on eBay and could not get them to work, after factory reset, they worked perfectly