How do I change the IP to other IP than 192.168.12.x?

  • 15 January 2022
  • 9 replies

Userlevel 1

I have an existing TPLINK AX11000 router that is setup with the 192.168.10.x network with a bunch of IOT devices in that subnet (static and dynamic addresses).  I am able to plug the Tmobile 5G gateway into the WAN port of my existing router and everything works as is.  (with Tmobile as the WAN network at 192.168.12.x)

However, all wifi and hardwired connections behind  my AX11000 router are at least 50% slower than devices that are connected directly to the Tmobile 5G gateway. Not sure if it is a double NAT latency that caused this.

Is there a way to change the IP on the Tmobile 5G gateway to use 192.168.10.x so I can modify my router to be switch/access point so they are on the same internal network.  it will be too cumbersome to change my internal devices to be on the 192.168.12.x and change my internal router to match.  


9 replies

Userlevel 1

I’m in the same boat and can’t find any info on how to change the served DHCP subnet on the device. Pretty disappointing from an otherwise decent services.

Userlevel 1

I just spoke with a Tmobile support team member.  Unfortunately there is no way to change the default IP address range on the Tmobile 5G home internet.  I will have to change all of my devices to be on the 192.168.12.x range if I want to flatten my network to be all on the same subnet.  

Not sure if the future firmware update will allow this change to happen. 

Userlevel 1


Thanks for the response!

I got the same answer from a support rep today. The level 1 rep I spoke with didn’t really understand the issue (he kept going back to / thinking it’s a wifi connectivity issue...) until I explained it 3 different ways. Finally he said it’s not possible. I asked him to submit a change request, which he said he would; and he said that all support calls are recorded (and inferred all were listened to - highly doubtful) and my query and suggestion would be heard.

We’ll see. I’ve never seen a router that didn’t allow the user to change its IP address and/or its DHCP range. While I like the service, this is a HUGE issue that needs to be addressed. It can be a show-stopper for some, and a real pain for most. Let’s hope a firmware update will do it and that they actually do address the issue.

I just ran into this issue after spendings 150$ on a website for my business to find out that I can’t even login in to the cpanel because my IP address continues to change and it logs me out I really hope they address this issue I need a static ip address or I will find a isp provider that does 

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TMO HI is basically CGNAT, with a sprinkling of psuedo VPN mechanics in play for their XLAT464 implementation to work... so you can't really get around the double-NAT scenario unless some MAJOR changes occur at higher network layers.

Also keep in mind if you are not linking the routers over ethernet, you will get that weird half-duplex wifi management that cuts throughput in a major way.  Also want to make sure that ethernet link is not registering as 100mbps.  Some routers have LAN or Switch management options that can impact realized throughput as well (may be an acceleration toggle, or something mentioning Cut Through Forwarding (CTF), etc.).  Sometimes this needs tweaking to actually achieve gigabit throughput all the way through the router.

About that TP link network... are all the devices using DHCP, or are there a lot of staticly set addresses in play?

You should have the option of running your router in access point mode.  This would allow everything to coexist in the same subnet, and if DHCP is in play they should behave fine, provided you bind their IP's in the gateway managing DHCP.  There are drawbacks of course, like nixing routing features in the TPLink, but it is an option that would still allow your TPLink wifi connections to work if it provides better/more consistent coverage than the TMO wifi.

Lack of ability to change LAN IP addressing is a pretty huge defect.  Carriers need to get their heads past the idea that the average home is only a laptop or two on wifi.  Granny with her iPad is not the target for this product, so why design the software limitations for Grandma’s ease of use?

It’s a new device though, and otherwise pretty exciting, so let’s hope better configurability is coming in the future.

I’m curious if one could just use DHCP guarding on a managed switch to block the “unauthorized” DHCP server built into the router--Allowing one’s own LAN server to handle DHCP without interference.  It won’t change the .12 addressing limitation, but at least it would make node IP assignment controllable.  

There are worse things than double NAT to be honest.  In fact, with more of a commercial setup, using NAT to deconflict overlapping address spaces is a thing.  

I am evaluating if I can replace a Cox cable modem service with this device.  It’s less than 1/3 the price of Cox for similar rated speed.  Around these parts, Cox has no actual competition, so they charge eyewatering amounts.  $164/month in my case.  I’ll go though some pain to drop my bill to $50 from $164.  Good for T-Mobile for coming to slay Goliath.  

But T-Mobile - let us configure the LAN settings!  Please!

Stuck in the same boat. Can’t change IP from the network. On top of that we need the availability to reserve IPs for devices. Or at least be able to adjust the dhcp pool. 

@Clearled as long as you don’t need port forwarding, you can just plug your own router into the ethernet port of the T-Mobile router.  Then everything on your lan should connect to your router— so for example don’t use the T-Mobile Wi-Fi, use the Wi-Fi built into your own router.  

This creates a situation called double NAT, which is recommended against, but also not really a big deal.  I’ve been running with double NAT ever since my post above and no problems.

I’m using a Mikrotik router and six Ubiquiti UniFi access points, my address space for everything stayed as  

The T-Mobile network of is being used as what we would call a transport network.  The only devices on it are the T-Mobile router and my Mikrotik router.  Everything else is behind the Mikrotik.


tl;dr:  Plug the wan port of your existing router into the lan port of the T-Mobile.  Don’t change anything else and it should work.  

If you don’t own your own router, such as you rented it from your previous carrier, just get yourself whatever router you like at Best Buy.  Anything will do DHCP reservations and allow adjustable pools—if it doesn’t it’s not a real router and you should take it back, lol.

Canceled the Cox service and I’m saving $110 a month!

as before the main problem is the need to engage in some fairly complex steps to create a reverse proxy to work around the idiotic carrier grade nat.  But if you do not need inbound ports forwarded, you can skip the worst part entirely.

I would also recommend disabling the Wi-Fi on the T-Mobile device, you’re not gonna be using it and it’s only gonna congest your RF spectrum.  you want that spectrum clear for your own router.

Its not a big deal … your internal ethernet can have a completely different network numbering scheme, mine is 10.0.0.x than the modem’s unchangeable silliness. And whom ever said it, you are completely correct, support hasn’t the vaguest idea what you’re talking I have both my own self built pfSense, and Untangle, now Arista (the free version works perfectly and is easier to work in than the pfSense one). You just set up and internal and external network, obviously you need to NICs, and tell the “external” one it's a WAN, and set it to DHCP, then set the other NIC for your internal (LAN) network. Arista cleverly figures this out, an you don’t even have to put any routes in. Boom, simple, not need to fiddle with useless “engineers” at T-Mobile.