Changing the DNS on your iPhone is quite easy. Usually, the Wi-Fi that you select on your iPhone automatically assigns the DNS based on router configuration. But occasionally, you might have to change the DNS yourself.
We’ll get to the reasons later. Here’s how to change the DNS setting on your iPhone or iPad. Note that this is a beginner post aimed at people who are unfamiliar with this (or new to iPhones/iPads). If you know this already, feel free to skip.
How to Change DNS on iPhone or iPad
Step #1. Open the Settings app → Tap on Wi-Fi.
Step #2. Pick a Wi-Fi network and tap on the blue “i” icon.
Step #3. Tap on Configure DNS under the label DNS.
Step #4. Tap on Manual → Tap on Add Server → Enter the DNS addresses (scroll down for free DNS servers.) Once done, tap on Save.
After doing this, you might want to restart Wi-Fi on the iPhone to see if the DNS change has taken effect. Next up, fire up Safari on your iPhone/iPad and check to see if web pages load correctly.
Free DNS Servers
I usually pick two DNS services (Google and OpenDNS) but there are like a gazillion DNS service providers out there. You can pick them from this list here.
Google: 18.104.22.168, 22.214.171.124
OpenDNS: 126.96.36.199, 188.8.131.52
You enter them as it is in the DNS field.
DNS Changes Sometimes Fix Wi-Fi Issues on iPhone
If you run into DNS-specific Wi-Fi issues on your iPhone, changing the DNS helps. Of course, this doesn’t happen all the time. When it does, you most likely run into Wi-Fi issues on all the connected devices that share the same DNS setting.
DNS servers are set by default in most cases. When the set DNS stops working, your Wi-Fi connectivity gets hit. A simple change in the DNS can fix it.
Troubleshooting a DNS Cache Problem on iPhone and iPad
Sometimes (very rarely), you might find that when you set a DNS, it doesn’t really take effect immediately. One fix that I’ve heard people use it to flush DNS
To flush the DNS cache, you just put your iPhone/iPad in Airplane Mode and then turn off Airplane Mode after a while.