If your iPhone Wi-Fi connection seems inexplicably slow, particularly when having moved from one wireless network to another, try manually setting custom DNS servers. This speeds up the response time and your wireless connectivity in general:
- Open Settings
- Tap on “Wi-Fi” and tap the blue arrow alongside the wi-fi network name you are connected to
- Tap the numbers next to “DNS” to change them
For the best results, use a tool in Mac OS X, Windows, or Linux like NameBench, a free utility to help find the fastest DNS server for your geographical location. Here are two choices that are typically very fast and reliable:
Google DNS servers: 188.8.131.52 and 184.108.40.206
OpenDNS servers: 220.127.116.11 and 18.104.22.168
This is a particularly worthwhile tip for those using older iOS devices like the iPhone 2G and iPhone 3G devices, but it can also make a noticeable difference for newer hardware including the iPhone 4, 4S, iPad, and iPad 2.