Tweak3D - Your Freakin' Tweakin' Source!
Windows 2000 Modem Tweak Guide [Page 4/4]

Posted: March 12, 2000
Written By: Keith "Farrel" McClellan

Additional Registry Keys

Here are some additional keys that I didn't find to help my system but may help yours depending on your particular configuration.

Under the [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters] Key:

TCPWindowSize - This setting should be set as a multiple of your Maximum Segment Size [MSS], which can be determined by your MTU-40. I recommend four times your MSS for 56k modem connections. For me this would be 5840. There are special instructions for modifying this key. Input the data as binary and then click on the hexadecimal radial button to convert to Hex before saving the setting.

Under the [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\] Key:

MTU - This allows you to manually input the optimal MTU for your system. This can be very dangerous - so be careful. The standard setting for this is 1500.

Determining your MTU

Depending on your particular modem/line/ISP, you may have more success with other settings. There is, however, an easy way to determine your optimal MTU, which should make your tinkering a lot less complicated. Start by opening a dos prompt, then enter the command "ping -f -l [trial MTU number] www.[your-isp].com". Start with 548 and go up or down depending on the message (if it tells you that the packets are being fragmented, you need to go down - you want the highest setting that doesn't cause packet fragmentation). To derive your MTU from the ping data, add 28 to the highest number that worked (packet size+28). Then, to derive your MSS from your MTU number, take MTU-40 and insert that value for MSS. The other settings will probably require a bit more tinkering though.

After you have performed these tweaks, you might want to check out MSN's Bandwidth Speed Test to see how well it worked. Compare an average of three, both before an after, and take into account the current connection speed and the speed it was connected at prior to tweaking.

File and Printer Sharing Security

File and Printer Sharing is not secure, and unless you are on a network you do NOT want to have it enabled. If you are on a network and there is no way you can set up a firewall of some sort, take the following steps:

(a) Put a password on all of your drives
(b) Set to Read Only - if you need to copy a file to a computer with read-only installed, go to the other computer and call the files from there instead of sending them.
(c) Disable File and Printer sharing within the Networking Tab of your Dialup Connection.

Internet Connection Sharing

Internet Connection sharing can be enabled from within the Sharing tab of your Dialup connection properties. For it to work, the other computers on your network must also support it (they need to have either Win2k or Win98 SE installed). You will want to enable on-demand dialing, but you probably won't need to fool around with the additional settings under the Settings button unless you are having trouble.


I hope this guide helps you guys braving the Win2K frontier out. Special thanks goes out to for their information on the placement of some of those registry keys. And as always, feel free to contact me with your questions and comments.

Click here for a printer friendly guide

First Page

  • News
  • Forums
  • Tweaks
  • Articles
  • Reviews