Unable to ssh through putty??

your_shadow03 · 09-15-2008, 01:53 AM

I am really surprised by this redhat box.I am able to login through ssh:// but am not able to login through putty.
it says: access denied permission.

And Also everytime I have to delete known_hosts file from /root/.ssh/ directory.

What might be the issue?

Pls help

matthewg42 · 09-15-2008, 02:28 AM

What sort of authentication are you using? password, public key...?

your_shadow03 · 09-15-2008, 03:22 AM

Its Completely a new RHEL4U6 system.I dint do any change to the system.It was installed yesterday.All I find is whenever I ssh through any other machine I find "SOMEONE NASTY IS GOING ON YOUR MACHINE" and it says to delete /root/.ssh/known_hosts file.But when I delete that file,it allows me.After Sometime If I will login through any other machine,it prevents me saying the same error.Again,I delete the file..and it goes on..

While through putty,it say :Access Denied" error

billymayday · 09-15-2008, 03:26 AM

Putty from same machine?

matthewg42 · 09-15-2008, 04:23 AM

The known_hosts file keeps a list of machines to which you have connected, and a cryptographic id of that machine. The point of the file is to make sure that when you re-connect to a machine which you have previously connected to, that it is the same machine.

What causes the message you see is that the remote machine's ID has changed. This can happen if the machine's identification keys are re-generated (e.g. you re-install the OS on the machine, or run the server key generation routine.

What it is trying to prevent is some attacker hijacking the machine's IP address and pretending to be that machine. An attacker might do this to get your password - if the attacker's machine has stolen the IP address of your machine, and you try to connect to it with a password, the attacker can steal your password.

If you are the owner/admin of the machine to which you are trying to connect, you should know if you have recently re-installed the OS, or re-generated the server keys. If you know you have done this, then it's fine to delete the known_hosts file. You will need to do this every time you re-generate the server keys or re-install the OS. The solution to the problem is simply not to regenerate the server keys. There is no reason to do it unless there is some known problem, such as the recent debian bug in ssh.

However, if you get this message at un-expected times, it is possible that someone is trying to steal your password.

your_shadow03 · 09-15-2008, 04:42 AM

By mistake I had run :
chmod -R 777 /root
Whenever I am trying logging in its hang on after providing password.
I checked with logs and it says

am_timestamp_check

am_timestamp: "/" permissions are lax

Whats That error all about?

your_shadow03 · 09-15-2008, 04:43 AM

And Now I am able to login as :

Code:

login as: root
root@10.14.236.132's password:
Last login: Mon Sep 15 14:39:59 2008 from 10.14.2.254
xset:  unable to open display ""
xset:  unable to open display ""
[root@Mplus ~]#

But after sometime It Again hanged...Whats Going On..Surprising

billymayday · 09-15-2008, 04:44 AM

/root isn't normally world readable.

What else did you do?

Was it chmod -R 777 /root

or chmod -R 777 /

?

your_shadow03 · 09-15-2008, 05:13 AM

No,
It was chmod -R 777 /root

your_shadow03 · 09-15-2008, 05:20 AM

Again....Its Just Sucks !!!

I thought have fixed the X session issue.Resolution: I tried running the following command

echo "export DISPLAY=:0" >> ~/.bashrc

And it solved the problem.

But When I am logging through putty it works ...but aftertime the putty goes inactive.

Why it happening?

billymayday · 09-15-2008, 05:21 AM

RHEL5, /root should be 750

The files within depend.

billymayday · 09-15-2008, 05:22 AM

This is one muddled thread - where did the X session bit come in?

your_shadow03 · 09-15-2008, 05:22 AM

Let me tel you something, recently I have upgraded my Redhat Linux from RHEL4U4 to RHEL4U6.

I am now Not able to login through ssh from any other machine too.

your_shadow03 · 09-15-2008, 05:23 AM

Sorry...Wrongly I entered into that..Pls Ignre it.

Can you go thru my last post...Pls Help

Is there logs entry which I can post for You for making things more simpler?I have no idea whats doing on wrong here?

vdx · 09-15-2008, 05:24 AM

check for the 22 no port is open on ur redhat system or not ?
is sshd running ?