Session Tab (Login Dialog)
Session tab contains the most basic session options.
The Host name box is where you type the name, or the IP address, of the server you want to connect to. Host name is the only mandatory box that must be filled for a session to open.
The Username box is where you type your account name on the server. If you do not fill the username and it needs to be known to complete authentication (most cases), you will be prompted for username then.
Unless at least Host name and Username are filled a session cannot be opened (Login button is disabled).
The Port number box lets you specify which port number on the server to connect to. SSH protocol uses port number 22 by default.
The Password box is for the password associated with the account. You are advised not to fill it in if you are going to save the session to stored session list. Also do not fill the password if you are going to use other authentication method (like public key). If you do not fill the password and other authentication methods fail (password has the lowest preference), you will be prompted for password then. Password storing can be restricted by system administrator.
Use the Private key file box to specify path to your private key file
if you are going to use public key authentication.
You can use environment variables in the path, with syntax
The file must be in
PuTTY format. If the private key is passphrase-protected, you will be
prompted for passphrase once the authentication begins.
If you have your private keys loaded into Pageant, leave the box blank,
unless you want to ensure that only that particular key is used for authentication.
The passphrase cannot be entered in advance on Login dialog and thus it cannot be saved to stored session. If you need to login to server automatically without prompt, generate key without passphrase. Use this method carefully and only under special circumstances.
The Protocol selection lets you choose transfer protocol.
By default SFTP is selected with option Allow SCP fallback enabled. With the option selected, WinSCP tries to find SFTP server and when it fails it initiates SCP protocol. Note that when fallback is disabled, WinSCP tries harder using non-standard methods to find the SFTP server. It is necessary to allow SFTP on SSH-1 server (read SFTP requirements for more).
You can see the protocol actually used on the Server and Protocol Information Dialog.