Help - Port 23

[iRonzel]

I make a firewall test in:  http://www.grc.com/x/ne.dll?rh1dkyd2

The results show that port 23 is open. The test was with Windows Firewall and then with ZoneAlarm Free (One at the time of course, I know the conflict that cause running 2 firewalls at the same time). And the results for  both firewalls was the same, port 23 open. 

I found this information about Port 23 (In the same site):

Port 23

Name: telnet

Purpose: Telnet

Description: Telnet is one of the earliest, original protocols of the Internet. A machine offering Telnet services is essentially offering to accept an "across the Internet" remote console terminal connection from any client device. This makes Telnet quite powerful and, without proper security, a significant security concern.

A Telnet client program presents a terminal-like window to its user and, when given a remote IP and optional port (port 23 is the default) attempts to connect to the remotely located machine to initiate a Telnet session. Since anyone with access to the network — or Internet — can access the Telnet server running in a device, the user must typically log onto the device with a user name and password.

Complete info here: http://www.grc.com/port_23.htm

Having this port open can be a security risk for my Pc?

[Pondus]

are you behind a router with a firewall ?
did you get this router from your ISP ?
do your ISP update / adjust settings in the router with Telnet ? ( this is how my ISP is doing it )

if you run the test with no firewall in your pc and get the same result then you have a router firewall
and if you are behind a router firewall when you are running the test, you will be testing the router firewall and not the one in your pc

[iRonzel]

are you behind a router with a firewall ?
did you get this router from your ISP ?
do your ISP update / adjust settings in the router with Telnet ? ( this is how my ISP is doing it )

if you run the test with no firewall in your pc and get the same result then you have a router firewall
and if you are behind a router firewall when you are running the test, you will be testing the router firewall and not the one in your pc

1. Yes
2. Yes
3. I don't know.

So, modifiying the settings in my router will fix the problem?

[polonus]

Hi iRanzel,

Do you have a router with attached storage devices, they may use this port.
"netstat -ano" at the cmd prompt will tell you the local ports that are
> open; look for ports in the "Listening" state. -o option give PID of
> prog that has the port open. You can add the PID column in task manager
> to see,

polonus

[Pondus]

So, modifiying the settings in my router will fix the problem?

you have to ask your ISP, they may use the Telnet port to control your router......

in my case i am not allowed / able to enter the router menu as it is locked by my ISP

[iRonzel]

So, modifiying the settings in my router will fix the problem?

you have to ask your ISP, they may use the Telnet port to control your router......

in my case i am not allowed / able to enter the router menu as it is locked by my ISP

In most case the serial number that is written in the back of router is the same for username/password. In my case i can enter to the Router and make changes, also i can see traffic event, change password for the wireless and more.

[iRonzel]

So, if my router have firewall, i don't need a firewall software in my pc?

At the moment I use Windows Firewall, in the other pc I installed ZA Free. (The latest released is very good and lighter than older versions). I thnking to install ZA in this machine. 

[DavidR]

So, if my router have firewall, i don't need a firewall software in my pc?

It entirely depends on if your router has outbound protection and the greatest majority don't, their firewall capability is only inbound. So for any outbound connection the inbound connection would allowed through as it originated from the local system. Now imagine a piece of malware gets past your defences, it would have freedom to connect and download more malware. So I feel outbound protection is essential, which means you have to confirm if your router provided this or you need a software firewall that does.

At the moment I use Windows Firewall, in the other pc I installed ZA Free. (The latest released is very good and lighter than older versions). I thnking to install ZA in this machine. 

If you are comfortable with ZA then that would be a start, though many would give you an argument on its suitability, but there are other choices.

Many forum users are using these:
- PC Tools Firewall seems to have the least user headaches as it doesn't seem to be constantly asking the user questions about this and that.
- Online Armor for the most parts fine but it has caused some users grief after avast program updates and that is something you have to watch out for.
- Outpost Firewall 2009 free, a cut down version of the Outpost Firewall Pro version, which should still provide good protection, http://free.agnitum.com/. Download, http://www.filehippo.com/download_outpost_firewall/