Why does Three (and Vodafone?) change IP address every 2 minutes?

[OM2]

I need to tether my internet connection and need a constant IP address.
I have some code that pings my server just to check my IP address.

Using a Three SIM, the damn IP number changes EVERY 1-2 minutes!!
Why is this? What reason could they have for doing this?

I've tried Three and Smarty, who use their network. (This is in the UK.)

I'm not 100% sure... but I think Vodafone does the same?
Can someone confirm this?

I use O2. The connection is solid. The IP address can change - but normally, you are good for a few hours at least.

Thanks.

 

[Hadron]

I can't say why 3 would be changing that quickly, you'd have to ask them (if you can get through to someone who can answer it). It may be for their own convenience, or it may be a deliberate choice because they think it helps your privacy or something (I think the first is more likely).

But why do you need a constant IP for tethering? This must be something to do with what you are connecting to, because tethering per se doesn't require this.

For what it's worth though, I just checked my mobile IP address on EE twice, about 30 minutes apart, and it hadn't changed.

 

[OM2]

Thanks for the reply
It's a long story why I need constant IP

Thanks for letting me know about EE
I will try them as well