How we can login to remote server through ssh?

#ssh user@servername

or

#ssh -l user servername

or

#ssh ip-add

So when you will execute the above command you will get the password prompt. But if you want to see what will happen when you execute ssh command you have to enable verbose or debugging mode. To do this we have to apply -v option at the time of login as shown in below example.

#ssh -v surendra@ftp2.linuxnix.com

root@krishna:/home/surendra# ssh -v surendra_a@ftp2.linuxnix.com
OpenSSH_5.5p1 Debian-4ubuntu4, OpenSSL 0.9.8o 01 Jun 2010
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to ftp2.linuxnix.com [92.32.56.78] port 22.
debug1: Connection established.
debug1: permanently_set_uid: 0/0
debug1: identity file /root/.ssh/id_rsa type -1
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: Remote protocol version 1.99, remote software version OpenSSH_4.0
debug1: match: OpenSSH_4.0 pat OpenSSH_4*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-4ubuntu4
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host ‘ftp2.linuxnix.com’ is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:1
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password,keyboard-interactive
debug1: Next authentication method: publickey
debug1: Trying private key: /root/.ssh/id_rsa
debug1: Trying private key: /root/.ssh/id_dsa
debug1: Next authentication method: keyboard-interactive
debug1: Authentications that can continue: publickey,password,keyboard-interactive
debug1: Next authentication method: password
surendra_a@ftp2.linuxnix.com’s password:
debug1: Authentication succeeded (password).
debug1: channel 0: new [client-session]
debug1: Entering interactive session.
debug1: Sending environment.
debug1: Sending env LANG = en_IN
Last login: Thu Dec 9 20:02:47 2010 from 1.23.6.79


After logout


debug1: client_input_channel_req: channel 0 rtype exit-status reply 0


debug1: channel 0: free: client-session, nchannels 1
Connection to ftp2.linuxnix.com closed.
Transferred: sent 2072, received 2072 bytes, in 27.7 seconds
Bytes per second: sent 74.8, received 74.8
debug1: Exit status 0

So if you want more verboseness you can use up to 3rd level(-vvv) as shown below

#ssh -vvv surendra_a@ftp2.linuxnix.com