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Bellevue, WA


telnet (mainly *nix, but some Windows support too)


Dublin, CA

Keep this closed

You should NEVER leave this port open on a server accessible from the internet. It is notoriously insecure. If you need to remotely access a server, use port 22 (ssh). What? Your OS doesn't support sshd? In that case, I suggest switching to a real OS.

Valley Stream, NY

Re: Keep this closed

Or add Cygwin to "unreal" OS
The Truth is out there

Elk Grove, CA

closing port 23

How do you close Port 23 on the 812ADSL Router? CLI and GUI doesn't have any specific settings...


Morganville, NJ

closing tcp23?

How does one close tcp23?

I have Windows ME and a Zyxel Prestige 642ME bridge at home. I'm using ADSL.

miss z


port 23

i don't have to worry about port 23 being open on my computer because my fire wall keep it closed all the time


Symatec Firewall says port 23 is closed!

Symantec Personal Firewall shows port 23 blocked local and remote. But the port scan test here showed it open. Anyone got an idea why?

San Juan, PR

Re: Symatec Firewall says port 23 is closed!

Port 23 is also used by your DSL/Cable modem so you can log into it. This may be why it's showing up as open. Nothing to worry about, since they won't/shouldn't allow access from anyone outside.

Green Bay, WI

port number not everything

keep in mind that the port number does not determine everything. running a telnet server and allowing it to be open to the public is bad, especially on port 23. it is merely a strong suggestion to run certain services on certain ports. i am frankly angry that security scores about my LAN that i submit are very bad because i have port 23 open and respond on it, but i am merely running ssh on port 22 which gets switched to port 23 as it goes through my by-hand configured firewall. i'm doing this because i have several computers running ssh on them that i want accessible from the internet.
although most of the time (especially from inexperienced users), having port 23 open is a bad thing, its not always.



For those that don't know....

Disable telnet in the services.msc console. That will close 23.



Re: For those that don't know....

ok can someone tell me where to find this,, I searched XP and found no info for that item. I need to close port 23

Destin, FL
If this is closed this will prevent remote desktop and XP Remote assistance won't it?
Mr Cowl Hood

Willow Springs, IL

Re: For those that don't know....

I too would like to know how to properly close port 23. If IS connected to my cable modem and closing it only prohibits remote desktop and XP assistance, is that necessarily a problem? It seems the need to close it outweighs that option....SO, how does one close this port 23?.....please?


how does one close a port?

I use winxp and its firewall on default, also I get routed through a dlink DI-724P+ router.

How do I close any port?, The test shows 21, 23, 80 as open



closing port 23 on xp

if you have xp with service pack 2 installed then simply turn on your firewall and port 23 will be closed.
New Milford, NJ

TCP Port 23

Port: 23
Service or Protocol Name: Telnet
RFC: 854



Telnet on Mac OS X
Because the Terminal application in Mac OS X can make Telnet and SSH connections, Mac OS X does not require a separate Telnet or SSH client, although you may still prefer to use one.


Telnet on WinXP

How to Telnet with Windows XP

The queen of hacker commands is telnet.
To get Windows help for telnet, in the cmd.exe window give the command:

C:\>telnet /?

Here's what you will get:

telnet [-a][-e escape char][-f log file][-l user][-t term][host
-a Attempt automatic logon. Same as -l option except uses the currently logged on user's name.
-e Escape character to enter telnet client prompt.
-f File name for client side logging
-l Specifies the user name to log in with on the remote system.
Requires that the remote system support the TELNET ENVIRON option.
-t Specifies terminal type.
Supported term types are vt100, vt52, ansi and vtnt only. host Specifies the hostname or IP address of the remote computer to connect to.

port Specifies a port number or service name.