Not possible without a jailbreak. Source: iPhone Configuration for OpenDNS It says, in part (emphasis mine): "These instructions only work for Wi-Fi connections because iOS does not allow you to change the DNS servers when connected to cellular networks.Also, the changes are network specific, so you'll need to change the DNS servers every time you connect to a new wireless network."
Jun 18, 2020 8 Tips to Fix Safari Cannot Find Server on iPhone – iMobie Solution 1: Check Internet Connection. Sometimes, due to your minor mistakes, you put yourself in … How to change the DNS server used by your iPhone and iPad Enter the Settings app on your iOS device, and select Wi-Fi. Tap the small "i" icon next to the name of the network that needs the DNS server details changed, scroll down, and tap Configure DNS. At How to clear the DNS cache on your iPhone, iPad & Mac
iCloud DNS Bypass - Remove iPhone Lock With Ease
May 15, 2015
Unlock iPhone/iPad with or without iCloud DNS Bypass
Aug 10, 2014 Simple DNS Bypass iCloud Activation Lock Or Remove iOS 12 DNS Bypass iCloud Activation Lock Or Remove iOS 11.1 Step by step instructions to Bypass iCloud Activation Lock on iPhone/iPad by means of Two Ways Bypass iCloud Activation Lock on iPhone/iPad by means of DNS . Restart your iDevice and pick your nation and dialect > Enter the new DNS server as: USA/North America: 104.154.51.7 ; Europe: 104.155 iNetTools - Ping,DNS,Port Scan on the App Store Oct 15, 2012 How to Bypass iPhone Activation Lock with DNS Server Bypass? Whenever you set up your iPhone following a factory reset or restore, your iPhone will send an activation request to Apple’s server to process the new device setup process. Activation Lock DNS Bypass is a method that allows you to avert the iCloud Lock mechanism.