Saturday, November 17, 2007

Hacking Your Modem For Gaining More Speed

Hacking Your Modem For Gaining More Speed
Hack Your Modem and Increase Your Download Speed from 64Kbps to any Speed You Wish

Most of us will be feeling that the surfing speed which is allocated by our ISP is not enough. People with 64Kbps will think 128Kbps will be cool speed. People with 128Kbps will think 256Kbps will be cool and so on

This tutorial will teach you how to increase your 64Kbps link to 512Kbps or what ever speed you like.

It is very much possible to do this. With a bit of luck if your Cable Internet Service Provider are very uneducated on how this very new technology works and leave some key loopholes open for you to grab vital information on how to accomplish this task. But this [tutorial] will no guarantee you 100% success.
Okay here we go. I'm going to try to explain you as best as I can to accomplish re-configuring your SB5100, SB4100 or SB3100 cable modem

Theory of cable modem working

All the cable modems when it boots up it will search for an "Image file" where in all configuration like your upload speed limit and download speed limit is defined. This "Image file" is stored in ISP`s TFTP server. Modem will be pre-configured with the ISP`s TFTP server IP address and the Image file name to be downloaded. When the modem boots up it query TFTP server and download Image file from [TFTP] [server] according to this this our speed limits will be set.
Our Mission

Get this Image file from ISP`s TFTP server, reconfigure it according to our need and force our modem to download this file from our Computer rather than downloading it from our ISP`s TFTP server.

1). Get cable [modems] MAC-address

You can either look at the back of the modem to get this MAC Address or you can logon to your Cable modem with your Web Browser hxxp:// . This is internal HTML pages stored within your DOCsis cable modem (SB5100, SB4100 and SB3100) that gives you even more vital information on configuration. Unless it is turned off by your ISP. This feature might be totally turned off by your ISP.
2). Get your [ISP] TFTP server IP address

a) There's a program called QUERY.EXE from Weird Solutions which is a BOOTP packet request program that will tell you everything you need to know, without all these extra steps. It will display the Image Filename, TFTP server address, which is really all you need to get started. To use this BOOTP QUERY tool, you need the MAC address of your cable modem or Beginners can use DOCSIS Diagnosis utility

Using the above tools you will get the information of your ISP`s TFTP server IP and the name of your "Image file" stored in that TFTP server

All your vital information is stored in this file, One of which is the MaxRateDown 2621440; MaxRateUp 393216;. (This was my ISP settings. Which you can see is similar to what speed I was getting. 40KB/s up and 250 KB/s down)

Among these, the one we need are:

Configuration [TFTP] [Server] = 194.*.*..90 (replace this with yours throughout in the doc)

Configuration filename = isrr.bin (replace this with yours throughout in the doc)


IP fragments created = 0

IP =

IP address. = (the IP address of the cable modem, (replace this with yours throughout in the doc) = 2

Suggestion: You can do this step by sniffing the modem i.e. "" when modem boots up. I never tried this method. Try your luck.

3) Download Image file from ISP`s TFTP server.

For doing this got to your command prompt and use below commands with out quotes and bracket.

"C:\tftp -i GET "

Okay now you got Image file from your ISP`s TFTP server.

4). Decrypt the Image file which you downloaded from ISP`s TFTP server
For all you can use the DOCsis tool to decode
5). Modify the Image file

Change your computer's TCP configuration same as ISP`s TFTP server (i.e. IP address same as ISP`s TFTP server)

Go to my network place and right click ->properties

Select your LAN Card right click ->property->Internet Protocol (TCP-IP) double click on it and change it to as following values

Configure your TPC's TCP settings as below

IP: 194.*.*.90 (replace with the ISP's TFTP server)


Gateway: (replace with your cable modem's IP address)

Note: Gateway should be then only your modem can communicate with computer.

6). Encrypt the modified Image file (Save it using Docsis)

7). Host TFTP server in your computer

Download TFTP Server software and host TFTP server in your computer

You can download TFTP server from: [content suppressed]

8). Put Image file in the base directory of your TFTP

Start TFTPD32 server. Go to Settings and set the Security to None. Increase the timeout to 20secs and the Max Retransmit to 6. Choose to translate UNIX filenames. Make sure it's base directory point to where the isrr.bin is (i.e. the image file which you modified). If you need to replicate a directory pathname along with the image file, then make a directory from root that corresponds to the image file pathname.

Restart your modem, and AS SOON as the SEND light goes solid, you should see a receive on your TFTP server i.e. your PC

9). [Restart] your [modem]

10). Changer your PC's IP back as given by ISP

11). OOPS Done. Start surfing with your new speed

Note: This speed will remain same until you restart your cable modem. So each time you reboot your modem you have to follow the steps 7 to 11

You can download TFTP server from: ftp: //