Hello,

I am working on a hardware device, it supports rsh (port513 and port 514 is open in device)
when I connect using putty (windows client) is shows login prompt, but when I connect using nc, telnet, rsh (linux clients) it does not show login prompt.

Purpose: I should be able to connect using a bash script or using a c code.

I am not able to understand this behavior, why its responding to putty client (win) only


Thank you
Sudhir

Welcome to LinuxQuestions.

Have you verified those services are actually running on your device and that the firewall if running is not blocking those ports?

Examine network traffic (with tcpdump or similar tool).

There is no firewall,
there is no issue with the device..
It is connecting with putty (from windows), it prompts for username and password.
but when I telnet to port 513, or use any other method to connect to port 513 of that device, it does not prompt for username password.
it is only responding to putty..

I will capture packets and check..

---------- Post added 10-12-14 at 09:13 AM ----------

There is no firewall,
there is no issue with the device..
It is connecting with putty (from windows), it prompts for username and password.
but when I telnet to port 513, or use any other method to connect to port 513 of that device, it does not prompt for username password.
it is only responding to putty..

I will capture packets and check..

I think you may be too focused on putty, and that is not correct.

You might better say it is only responding to the Windows machine running putty, but not responding to the Linux machines.

Are there firewalls or other network "obstructions" between the Linux machines and the device?

telnet does not understand the rsh protocol so it isn't a surprise that it does not work.

I assume that you can connect on the rsh server itself.

When trying to connect from a linux client are there any error messages? If so please post them. What distribution/version is the client running?

So connecting works from Windows (you might try other clients, e.g. dtelnet), but doesn't work from linux. Configuration difference.

I Installed putty on Ubuntu
tried with telnet -r , and nc.
its responding to putty on windows and Linux both.
My requirement is , I need to connect and authenticate to rlogin (Sorry its not rsh)
using a c program or shell script.

---------- Post added 10-13-14 at 10:15 AM ----------

I Installed putty on Ubuntu
tried with telnet -r , and nc.
its responding to putty on windows and Linux both.
My requirement is , I need to connect and authenticate to rlogin (Sorry its not rsh)
using a c program or shell script.

Because rlogin,rsh is insecure it has been replaced by ssh. I assume they are actually symlinks to ssh in Ubuntu which is why you are having problems. You can install the real rlogin client via the package rsh-client or rsh-redone-client (fixes bugs and includes IPV6 support).