MacOS – Slow connection to the particular brand of router over WiFi with Lion on MacBook Pro

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I own a MacBook Pro for some months now, it came with OS X Lion pre-installed. Since then, surfing the net with it is painful due to slowness. I also have a MacBook with Snow Leopard on it, there the internet works at normal speed. Based on this I conclude the problem is inside the MacBook Pro – it shows full WLAN connectivity but loading Google takes forever. My Router is a AVM Fritz!Box.

What I tried so far to optimize the speed – unless (noted) the changes made below don't affect the measured latency or speed at which pages render:

  • Resetting the router, turning WLAN on and off
  • Switching WLAN channels, trying 802.11n+a and 802.11n+g
  • Deleting all Wi-Fi networks in the system preferences
  • Resetting PRAM and NVRAM
  • Re-starting the MacBook Pro multiple times in a row
  • Disable iCloud in system preferences
  • Using another Browser than Safari
  • Renaming the network
  • Disableing "Use channels optimized for 300 Mbit/s" in my router (this helped, but still not to equal the speed of Snow Leopard)

What else could I try? I read changing the DNS server Google's can help, bit to my understanding, this really can't fix the problem. Reinstalling is not an option. I am really desperate to solve this problem because it is more than annoying!

Best Answer

Have you tried flushing the DNS cache? In Terminal.app, enter dscacheutil -flushcache.


It could be your DHCP router handing out IPv6 information incorrectly, which is especially annoying if you don’t need IPv6 — like at home. This seems like the most logical explanation, given that all browsers and applications are suffering from the speed issues.

Go to System Preferences → Network → WiFi → Advanced → TCP/IP and set “Configure IPv6” to “Link-local only”.