SSH Troubleshooting

• If you have problems with SSH, here are some troubleshooting pointers:
  Run ssh -v (verbose option) to see additional information, which is often helpful.
• If the ssh-daemon is running on a port different from the conventional 22, make sure you are specifying port -p 221 (for instance).
• Check that your home directory or SSH subdirectory does not allow world or group write access.
• If you are attempting to use RSA authentication, check that you have not introduced carriage returns when copying identity.pub contents into the authorized_keys file.
• When you are asked:
  Host key not found from the list of known hosts.
  Are you sure you want to continue connecting (yes/no)?
  
  Respond yes, but be aware the response should be yes and not y.
  
  If you see a message that begins:
  @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
  WARNING: HOST IDENTIFICATION HAS CHANGED!
  @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
  IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
  Someone could be eavesdropping on you right now
  (man-in-the-middle attack)!
  . . .
  Are you sure you want to continue connecting (yes/no)?
  
  it is likely that the host key in use by the remote system has been changed. Here is what to do:
  
  Edit your local ~/.ssh/known_hosts file to remove lines containing the name of the host you were attempting to reach.
  Retry the SSH command and when asked "Are you sure you want to continue connecting?" answer "yes."
  
• Is SSH possible? The host you are trying to access must have SSH installed and must be running the SSH daemon.
• If your SSH usage involves non-interactive connections such as with pvm or batch submissions, a passphrase cannot be used.

Further reading:A good article is on http://www.llnl.gov/computing/hpc/access/ssh_outside.html

Exceed just flashes and closes after login!

I had to restart my PC for some reasons. I had closed my Exceed Session earlier-on and again launched it after restart.
Everything was normal until I logged in. After I logged in, the Screen just flashed and down it went... disappeared!! Oh man! Not on a Friday afternoon!

I sighed a little thinking it was just one of those program _crashes_. Went about the typical stuff of seeing whether any "Exceed" related program is running on the TaskMgr, killed it and then restarted Exceed.
The login screen came - alright; but now after I logged in, it again came back to the login screen!! I suspected my password expiry and checked the connection to our Dev-Host via telnet. Everything was fine.

Now, I reinstalled Hummingbird Exceed 7.1.xx that I was using; replaced it with 9.x and tried again - Still the same problem! Just to make sure, I had one of my colleagues login to the host from my machine. It worked!

It was now clear that it was something to do with my XWindow configuration that had gone wrong OR possibly corrupted.
I tried Google/Yahoo and stuff I could find with my intelligent key-words; bah, No help.

Finally I raised it with our Unix Team; not expecting replies till monday.
And down comes the quick mail from the senior SA - A one-liner that said:

Log in through a normal ssh/telnet session - move your .dt directory out of the way (or remove the sessions directory inside it).

So, thats what I did: I first tried deleting the sessions directory $ rm -rf

${HOME}/.dt/sessions - Didn't work.

And then, I tried doing the next bit:

$ mv .dt .dt1
: Logged in again and I was through..!

The only problem was that I had to re-setup my workspaces and their names just as I had before - hmm., thats not a hard job is it..!

- 12 Jun 2006

WinXP: Unable to write to Flash/Removable Storage

Like most of you, I fancy carrying a USB-memory-stick with me most of the time. One fine monday morning, I had to pick a few snaps from my PC and copy them over a friend's laptop. Simple, as it should be - it didn't work!!


I was not able to copy files from my machine to the drive! It would read like a breeze, but simply wouldn't copy! Tried the same on the laptop, and it works! After a few tries on google, I gave up to the fact(?) that it was a hardware issue.


A couple of hours later, I tried with some "smart"-er keywords which brought me to a long article on people complaining about USB issues. Somewhere down the line, this XP demi-god had quoted a solution.

Its to do with a registry setting, usually reset after XP-SP2:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies\Writeprotect

is to be set to zero "0".


That was it! Simple and neat!
PS: You may need admin rights to set this key.