Internet service and VoIP

Today I have fixed the VOIP issue with T-mobile Home Internet and VOIP.  

Firstly T-mobile to prevent outside packet attacks to susceptible ports 5060 and 5061 updated their settings to not allow through Sip protocol through those ports. 

You cannot access the backend of the modem and outside modems that are highly modifiable like the Gli.net 5G modem. Don't work to assist you in the matter, because its a block by the server end of T-mobile not the routers themselves. 

I know this because I tried every means to configure the GL-X3000 Spitz modem to work with t-mobile over the last month and it would not go.

So, now the only solution since it's not a user side issue or router issue, is to bypass the T-mobile network settings blocking your 5060 and 5061 SIP ports. 

Here is how you can go around this. This... was such an easy fix I wanted to cry.

Step 1: Call your hosting VOIP network operator. 

Step 2: Have them go to network settings on your VOIP system background. 

Step 3: Turn you UDP port 5060 and 5061 to TCP

Step 4: Turn off your VOIP devices, servers, programs and applications. 

Step 5: Turn them back on and now you can make outbound calls and inbound calls without issue.

Works for Max UC and other VOIP services, Verified. 

You are welcome. 

syaoran wrote:

No and VOIP services do not work with T-Mobike Home Internet in most cases.  VOIP lines aren't the same as home phone services either.  The gate here actually requires a local number and a landline, not a VOIP service or cell service.  Not too sure if the system at your property works the same.

It may have changed since you replied, but I’m using a VoIP phone through GoToConnect with T-Mobile Home Internet without any issue. Of course, the elevator referenced in the question you were answering will still require a wired phone line, but VoIP does work. 

I wanted to post an update. I was able to resolve the issue with T-Mobile by creating a VPN (virtual private network) server on my home fiber network in Minneapolis, I then obtained a router with VPN client and put it between my T-Mobile gateway and VOIP phone at the other location (Tucson). The VPN “pipe” tween the client and server passes VOIP traffic in an encapsulated manner, unaffected by whatever T-Mobile is doing. I could to do this only because I have two locations available, with two different ISP’s (T-Mobile and US Internet), in other words, I leveraged my fiber network at my other home to hide the VOIP connection from T-Mobile. This solution cost me $32 (Amazon price for the GL.iNet GL-SFT1200 router).

That is very interesting. I checked and my KVD21 is also running version 1.00.22. I went to the CallCentric website and verify that it was a VOIP service similar to VOIP.MS, which it is. So now I wonder if there's something in the CallCentric configuration that allows your VOIP to work but not mine. I use a Cisco SPA525G2 phone. So what I will do is check CallCentrics configuration guide for the SPA525 to see if there is something I can change to make mine work again.

@MixedBag, I have the KVD21 with firmware version 1.00.22.  My VOIP service with a GrandStream HT801 ATA using CallCentric was been working flawlessly for over a year. I’m keeping my fingers crossed that things don’t change, but trying to understand why my VOIP with TMHI is still working, when I hear about others having the issues like you’re experiencing.

I have been following this thread for some time as my VOIP service with VOIP.MS (and all other VOIP lines) suddenly stopped working late April 2024 (it was working for over a year). 

A couple of days ago, I decided to call T-Mobile customer support to see what my experience would be like.  I convinced them to escalate my issue to the Business support team since this is more of a business type of issue. I was offered Ooma, which is apparently a T-Mobile service, but I declined since I use my own PBXs and other 3rd party VOIP services. What I got them to admit is that a recent upgrade to the KVD21 (also to the new TMO G4AR gateway) prevents T-Mobile Home Internet end users from using 3rd party VOIP services. The reasoning behind this could not be explained even though I tried to extract this information, it was apparently at a “higher pay grade” than the technician I was speaking to. Long story shorter… the solution is to use my Inseego M2000 portable hotspot for VOIP.

We can hope is that if enough of us protest this feature change (“its not a bug, it’s a feature”), the engineers will revert what ever they did to block use of VOIP on T-Mobiles Internet service in a future release.

@henry51 Thanks for the info, not sure I can get my number ported (which would be a hassle) but I’ll check it out.  My non-VOIP concerns about the service are my highest priority as I can’t assign static IPs impacting my NAS functionality.  TMHI must listen and make some changes for advanced users...

@JomaTX Would a different VOIP service meet your needs?  I’ve had CallCentric https://www.callcentric.com for a few years now (even when I had a different ISP).  TMHI and CallCentric seem to get along fine.  It might be worth a try before you leave TMHI.

Same here as many of you.  t-Mobile doesn’t support my VOIP (phonepower) service.  I can receive calls, but not make outbound calls.  Had to upgrade from my OBI200 to make that work, but new Grandstream device only got me inbound calls.  Tech support says it’s a IPv6 issue and lack of movement from t-Mobile.  VOIP isn’t the only issue, but the inability to configure static IPs for my network is even worse.  Love the 5G service for speed, but half my network needs are now unfulfilled.  Will jump t-Mobile as soon as better option is available.  Loyalty is earned…

@TFedup I think the information in your post will be very useful to those who are experiencing issues with their CallCentric/TMHI setup. The configuration of my GrandStream HT801 has had sip.callcentric.net for several years now. It’s working like a charm.  Thanks for sharing!