No Echo Back on Telnet Connection to port 23 vs echo back OK on other connections

[John Froese_1]

Hello,
-I am trying to figure out a problem connecting to network elements in a system I administer. I am using a terminal emulator 'SwitchTerm' and opening the SwitchTerm connection from within an application. This application has a configurable setting when running the application as follows:
exec /share/switchterm/SwitchTerm/SwT/HPUX1020/mvterm -sl 5000 \
-title "$titleString $Title" \
-n "$iconNameString" \
-geometry "$emulatorGeometry"x24 -sb +rc \
-e $runProgString $paramString
;;


Normally , the connections I manage are telnet connections to Serial Ports via a Terminal Server, where I configure telnet connections as IP 192.168.1.1 and port 2001(for the Terminal Server port) This works fine.
-However recently when I connect to an IP device directly, as in telnet 192.168.1.1 port 23. I get the connection OK and can login to the device but see no echo back.
- I am wondering if someone can explain to me the different requirements in getting echo back with connecting to 'port 2001' vs 'port 23' ?
-Could the application be requiring differnet settings for one connection vs the other?

Any help is much appreciated.
Thanks!
John Froese

[Ralf Seefeldt]

Hello John,

I do not know whether there is a router or a firewall in between your computer and the computer, youare connecting to (probably, the firewalls even runns on your computer).

Ports below 1024 are regularly blocked by firewalls and routers for they belong to well known and established services (defined by RFC 1700). Ports above 1023 are often used from many programs for opening reply-communications and are not blocked in many networks.

Please make sure, you do not have a problem with a firewall, blocking port 23 from the remote station to your local one.

You might get the firewall/router reconfigured or tell your telnet daemon to listen to a higher port (in /etc/services)1

[Muthukumar_5]

May be a problem with stty setting for echo.

Put like,

stty echo

to get echo back setting.

--
Muthu

[Muthukumar_5]

Put that stty echo into /etc/profile or $HOME/.profile file. It will give echo back setting.

23 is default port. Which can be controlled by firewall or /var/adm/inetd.sec file to block user access. If the connection is ok and not echo back then stty setting problem is there.

--
Muthu

[John Froese_1]

Thanks for the replies folks!
I am still having problems though, and will try to explain a little better.

I added 'stty echo' to my .profile on one server to test as you suggested, Muthu, but the problem remains. Actually when I directly telnet to the IP in question, I get a local echo with this line in my .profile or not. The issue can be explained better as follows:

It occurs in at least two scenarios-
1.from an application which I described earlier - note this application is run using Exceed to send a display back to my PC,
2. from the cmd prompt on my PC - I telnet to this IP and port and get no local echo when I enter a userid I am prompted for, and then I get **** when I enter the password. This is the same ( Also occurrs using HyperTerm)


But when I use Putty telnet from my PC - it is fine - I see echo of my userid - but do not see **** when I type my password .

Could this be a setting in my PC?

[DaVinci_1]

Hi John,

I would check to see if local echo is turned on in the SwitchTerm Window.

Preferences -> Terminal Settings -> Local Echo

Also, you can check the SwitchTerm resource file for Mvterm.localecho value and see if it is set to true.

thanks,
DaVinci