Question

IP Flapping on Home Internet interfering with access to several online services

  • 14 December 2022
  • 4 replies
  • 280 views

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I have had T-Mobile Home Internet for a couple of months now. Previously I have had numerous brands of internet service: Verizon, AT&T, Solis(AT$T, Verizon & T-Mobile). With T-Mobile Home Internet I cannot use several sites that have never been a problem:

  • I can’t get an FTP connection to work.
  • I can’t use my banks bill pay.
  • I can’t log in to another financial institution. 

I’m told that this is due to “IP Flapping”. I have NEVER had this problem before and have been using the now inaccessible sites for years. 

 

Can T-Mobile fix this problem? 


4 replies

Userlevel 7
Badge +8

I have seen an article that suggest that T-Mobile shares IPv4 addresses in its operation with the 464XLAT solution. I don’t know why the IP addresses should change as rapidly as they do. T-Mobile has 13,232,896 IP addresses but also “more than 110 million subscribers as of the end of Q2 2022” so if you consider the number of devices each subscriber may use at any given time the numbers grow quite a bit. There is a very good reason they use IPv6. They are looking forward and need to scale the network to continue to expand services. 

Interesting information for those who like to know and understand tech things:

https://ipinfo.io/AS21928 

Sorry I posted the link that was for Netflix

T-Mobile has 13,232,896 IP addresses and 573 hosted domains.

Userlevel 5
Badge +7

I'm located in S. Florida and don't see the behavior you're describing. I am able to pay from both Chase and BOA with no problem. My IP stays steady, although I am behind a Mullvad VPN. I disconnected for a few hours to monitor my IP and didn't see it change at all.

What does TM say when you contact them about this?

 

Userlevel 7
Badge +8

I have not contacted T-Mobile about it as it has caused me no impact. I have watched my IPv4 address change and then searched at https://ipinfo.io/AS21928  to locate where the various IPv4 addresses are hosted. I can see they are in Atlanta. They are all from the same Class B subnet so that makes sense to me. 

I think the problem with some applications having issue with the changing IP address is due to how they geolocate based upon the IP address. It is probably tied to how the specific use of the IP address is with that institution. Like with streaming services that want to lock onto a specific host address for location. Not the best practice to have where IP addresses can be changing in a specific provider network. 

Userlevel 7
Badge +8

I just went to “whatismyipaddress.com” and checked my IPv4 address repeatedly after about 5 second intervals. I saw it change 5 times with 4 different addresses. It continues to do so just rotating. Prior to this week I had seen the IP address change maybe once every few days or once a week but now it seems to be flipping pretty constantly. 

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