iPhone How do I change DNS on 3G /LTE ?

[urfeen]

I have very slow internet when I switch to from Wi-Fi and browse in cellular ( 3G or LTE).
I suspect it because of wrong internet settings provided by T-mobile ( Poland).
If there is a way to change my DNS or specify which DNS to use via Safari command line ?
[iPhone 5S no jailbreak 8.4]

 

[urfeen]

I found the solution:
* it is not possible to adjust IP settings without Jailbreak
* the workaround worked for me :
Reset network setting WITHOUT SIM card inside and then reboot with Home+ Power

 

[pinebeltdesign]

You can't change DNS in iOS for cellular data.