How to Adjust MTU Settings
Changinf MTU value for Windows computers
We would recommend adjusting the MTU setting to 1372. http://support.microsoft.com/kb/826159 you will find a section that states "Change the MTU Settings for VPN Connections" or http://help.expedient.com/broadband/mtu.shtml
Changing MTU value For Mac computers
We would recommend adjusting the MTU setting to 1372. http://docs.info.apple.com/article.html?artnum=303192