Internet Connection Sharing

[John]

I have a W2K Pro desktop with an Internet connection. I
also have a small P2P network setup. I 've enable
Internet connection sharing from the W2kPro Desktop. The
problem I am having is I can go anywhere on the internet
from the Win2K pro Desktop, but the clients (remote
systems 98, XP, and 2000) on my LAN can't seem to get to
certain sites through the ICS setup.

I've uninstalled and re-installed ICS. Removed all Virus
scanning. Tested all DHCP settings. I can Ping across
local network?.... What am I doing Wrong????

 

[William Lipp]

It sounds like you are suffering from the problem that ICS is a Black
Hole Router. Read about Black Hole Routers here:
http://support.microsoft.com/?id=314825

To see the Black Hole behavior, try these two commands from a DOS
window on the Gateway machine and the other machines:

ping www.ebay.com -f -l 1472
ping www.ebay.com -f -l 1432

Also try www.google.com and www.abcnews.go.com. The gateway machine
for 1472 will respond "packet needs to be fragmented but DF Set."
All other setting will respond "Request timed out." When browsing,
the gateway machine sees the message and reconnects with a smaller
MTU. Bu the gateway never relays this information to the ICS clients.

The workaround is to use Method 3 from the article and set the MTU
size of the client machines to 1460 (=1432+28).

I'm hoping that one of the pros here will pick up on this and get
Microsoft to fix ICS.

 

[Michael Johnston [MSFT]]

This sounds like a MTU issue. For more info on how to fix it refer to 319661 Connectivity Problems on ICS Clients When You Use
a PPPoE Connection on http://support.microsoft.com/?id=319661

Thank you,
Mike Johnston
Microsoft Network Support
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