Fix: Youtube buffering issue

Over the past two weeks I’ve noticed a continuous issue with loading youtube videos and having them endlessly buffer. Tonight I did some digging and found a quick fix!
The solution is pretty simple, and involves blocking a specific IP range associated with Verizon FIOS servers which are buffering Youtube traffic.  Since the IP may be different depending on your location I’ll go through the simple steps to identify the IP to block and the associated OS X command to run to block it.

1. Open a terminal window and type “traceroute youtube.com”
2. Note the first IP address which shows up outside of your network.  It should be the one which doesn’t start with 192.x.x.x
On my network the offending IP is:
l100.<your area>-vfttp-<some number>.verizon-gni.net (1.1.1.1)  19.260 ms  20.116 ms  18.862 ms
Also, note any entries which end in “alter.net” as these are Verizon FIOS servers.
3. Test loading a highdef youtube video.  Make sure to switch its resolution up to 1080p, and watch it buffer.
4. From the terminal window block the offending IP by running the following command
sudo ipfw add reject src-ip 1.1.0.0/16 in
5. Confirm the IP is now blocked by running sudo ipfw list
Example output:
00100 reject ip from 1.1.0.0/16 to any in
6. Refresh your browser by hitting F5 and reload the high def YouTube video.
Note, if this doesn’t work the blocked IP subnet can be removed using the following command:
sudo delete 00100 reject ip from 1.1.0.0/16 to any in
If this doesn’t work you can also try blocking the IPs found within this post.