[etc] How to Use SSH2

THIS IS OUTDATED. THE UPDATED VERSION IS AVAIALBLE HERE

 

This is the most simplest tutorial of SSH. I had been surfing the Internet for a long

time to get this done, but it was not getting done.

Here are the steps that anyone should follow.

USE SSH2, as this is much better than SSH1 and also the newest standard.

I have been using OpenSSH and SecureCRT, and the SSH product that comes with Solaris (i dunno which).

 

Local Machine (client): Mia

Server Machine (sshd server): Ghulam

 

STEP 1: Creating and ssh key

 

mia%~> ssh-keygen -t rsa            (other options are rsa1-> for ssh1, dsa-> for ssh2+dsa)
Generating public/private rsa key pair.
Enter file in which to save the key (/home/shashank/.ssh/id_rsa): PRESS ENTER
Enter passphrase (empty for no passphrase): secretpassword 
Enter same passphrase again: secretpassword
Your identification has been saved in /home/shashank/.ssh/id_rsa.
Your public key has been saved in /home/shashank/.ssh/id_rsa.pub.
The key fingerprint is:
45:2b:41:a2:22:04:ed:ad:2d:0f:1b:b3:1d:9f:e3:5e shashank@mia

 

(Enter a passphrase when prompted. NOTE this is a passphrase and not PASSWORD that u use for logging in.

Thus any valid passphrase will work. This passphrase is just used to encrpt the private key, so that

others cannot read it)

 

STEP 2: Check the /home/shashank/.ssh/id_rsa.pub

It should look something similar to this:

 

ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEAwPvDSPO18NPH4p0RylhROgfL/4nz8+xHUl6olSWq2RqSXACdR6rzlytT8QPdHEgBM8

YsmYsGTKxbqNIMMivROmcfcKStViQO0Tgl7ZGSjKjzB6mLtS9DjQPYm/J1hQRASdY9JCs80PyGHuSu4QezY+jY9/

Opj8ZLB2WjgO7fFiU= shashank@mia

 

 

STEP 3: Append /home/shashank/.ssh/id_rsa.pub (on Mia, client machine) file to ~/.ssh/authorized_keys on

server machine(ghulam) that u want to log-in.

In this case, let us say, that i want to log into an account shashank@ghulam.

I will do the following:

mia%~> scp ~/.ssh/id_rsa.pub shashank@ghulam:~/.ssh/id_rsa_mia.pub

(In the above command, I am transferring my public key on mia, to my account "shashank" on ghulam, and renaming it as

id_rsa_mia.pub.. The renaming will make sure that u do not overwrite the public key present on ghulam..

You don't have to use scp, and u can use ftp or email to transfer the public ket from mia.)

 

After the above step, i log on to ghulam and append the id_rsa_mia.pub file contents to the end of

~/.ssh/authorized_keys file present on shashank@ghulam. NOTE if this file is not present, just create a new file.

 
 

 

NOTE: You local public key must be recorded in the authorized_keys file of the server

where u want to log-in.

 

 

STEP 4: on local machine (Mia) start ssh-agent and ssh-add

 

do the following

mia%~> ssh-agent $SHELL
mia%~> ssh-add

 

This will ask for you to enter the "Passphrase"  (secretpassword) only ONCE. Enter that and it will

return to the prompt. Now from here onwards, u don't have to enter the password for

anything (ssh or scp or anything)

 

thats it,.

 

Suppose u are using secureCRT. In this case, u will need to transfer the Identity.pub file.

You can find the location of this file by going to Options->Global Sessions->SSH2 in SecureCRT.

 

Just transmit this file to the server. Note that this file is of the form

---- BEGIN SSH2 PUBLIC KEY ----
Subject: shashank
Comment: shashank@film
AAAAB3NzaC1yc2EAAAADAQABAAAAgQC6IlFxDO2viAwSzGqxzwiHNWqrePmi22L84Cru
R85IDUXULNzOe3NvPa/fA2OA6qWbHQIpQFOlbTwodpKqWQIcSceYupd/EEcgC1tc/lYg
g4lc9aAkvU0LKEsb54YXly0RyhVo22+eC7l35mv2YYb3HZbG3VTrMlMekh91UiXm6w==
---- END SSH2 PUBLIC KEY ----

 

So u cannot add it directly to authorized_keys on the server.

U will have to use a command at the server to convert it to the standard form

 

ghulam> ssh-keygen -X -f ~/.ssh/Identity.pub >> temp_keys2

 

the above command will convert the public key to the below form

ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAAAgQC6IlFxDO2viAwSzGqxzwiHNWqrePmi22L84CruR85IDUXULNzOe3NvPa/

fA2OA6qWbHQIpQFOlbTwodpKqWQIcSceYupd/EEcgC1tc/lYgg4lc9aAkvU0LKEsb54YXly0RyhVo22+eC7l35mv2YYb3

HZbG3VTrMlMekh91UiXm6w==

 

Append the abpve at the end of authorized_keys (again if authorized_keys is not present, just create it).

Everything eles should be OK.,

Also remember to use the authentication as "Public Key" and then "password" in secureCRT.

 

 

Some important ssh comands:

ssh shashank@ghulam (for logging in)

scp temp shashank@ghulam:~/temp/ (to transfer local temp file to ghulam)

 

if u use "-v" option in the above command, you will get a lot of debugging messages,

which provide very useful messages.

 

 

Regards
Shashank
http://mia.ece.uic.edu/~papers