MTU stuck at 1480 for Windows XP? Or 1486 for Windows 2000
Unfortunately, Windows XP's default MTU setting is 1480 with it's built in PPPoE software. There is no way to get around this... with that PPPoE client. Only way is by downloading RASPPPoE. Before you install it, your current connection MUST be deleted, otherwise you will get errors. To delete your current connection, right click My Network Places and select Properties. Your connection should be under Broadband Connections. Right click >disconnect, then right click > delete. Then install RASPPPoE by reading the Windows 2000/XP instructions that came with RASPPPoE. Be sure to read everything carefully, because some instructions are specifically for Windows XP.
If you want an always on connection for RASPPPoE then scroll down in the instructions, it will teach you how.

 

In some cases as the above for windows 2000 it will be set at 1486 this can happen with the connection from the ISP this is well known on Pacbell and in some cases with Earthlink we’re not sure with the rest of the ISP’s if you find this to be true with your ISP let us know either in the forum or send us a email