Telnet in IE8

I followed the instructions and it worked  perfectly. I can now click on my telnet in IE8 and it opens. It was just a matter of a registry hack. Hope this helps.

Actually, you aren't actually using IE for telnet, it just calls the built in client so you are using a real client. It is an easier way to start the telnet client though.

The wording can be confusing. You create a new Dword value (the DWORD Name part) which contains Data (the DWORD Value part).You can't rename the Default value.You right click in the right pane, point to New, click Dword value. A new Name will appear named New Value #1. Should already be highlighted ready to rename. Then name that new item iexplore.exe. You then double
click it and set it to zero, though it should already be zero.

It does work for IE8.

I took an XP SP2 box with IE6, installed IE8, added the registry key, rebooted, and Telnet works fine. I did get a prompt asking Do you want to allow this website to open a program on your computer?
You can uncheck the box so you won't be prompted for Telnet://  addresses again.

You can copy the text in the following code block into Notepad, save it as a .reg file (Be sure to change the Save as Type box to All Files) and double click to create the entry. I've included a line to
remove the one with the extraneous space if it exists.
Code:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_ MACHINE\SOFTWARE \Microsoft\ Internet
Explorer\Main\ FeatureControl\ FEATURE_DISABLE_ TELNET_PROTOCOL]
"iexplore.exe" =dword:00000000

My telnet shell command already had the rundll32 part. That the website linked above doesn't have the correct value though. It should include the full path as that makes it harder for malware to interfere:
Code:

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ ROOT\telnet\ shell\open\ command]
@="\"C:\\WINDOWS\ \system32\ \rundll32. exe\"
\"C:\\WINDOWS\ \system32\ \url.dll\ ",TelnetProtocol Handler %l"

Note that the last character is actually a lowercase letter L, not the number 1.
If your Windows folder is not on C: or is named something else, you'd need to modify that to match your system, or use this version which uses the %Systemroot% variable instead of hard coding the path:
Code:

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ ROOT\telnet\ shell\open\ command]
@=hex(2):25, 00,53,00, 79,00,73, 00,74,00, 65,00,6d, 00,72,00, 6f,00,6f, \

00,74,00,25, 00,5c,00, 73,00,79, 00,73,00, 74,00,65, 00,6d,00, 33,00,32, 00,5c,00, \

72,00,75,00, 6e,00,64, 00,6c,00, 6c,00,33, 00,32,00, 2e,00,65, 00,78,00, 65,00,20, \

00,25,00,53, 00,79,00, 73,00,74, 00,65,00, 6d,00,72, 00,6f,00, 6f,00,74, 00,25,00, \

5c,00,73,00, 79,00,73, 00,74,00, 65,00,6d, 00,33,00, 32,00,5c, 00,75,00, 72,00,6c, \

00,2e,00,64, 00,6c,00, 6c,00,2c, 00,54,00, 65,00,6c, 00,6e,00, 65,00,74, 00,50,00, \

72,00,6f,00, 74,00,6f, 00,63,00, 6f,00,6c, 00,48,00, 61,00,6e, 00,64,00, 6c,00,65, \
00,72,00,20, 00,25,00, 6c,00,00, 00