Menu option: Options > Preferences > Spider passwords

You can use the Spider passwords settings to store a user name and password for sites that require login. Note that any password information you store this way will be accessible to anyone else who uses this computer, or who has access to your files.
Server
The name of the server where the web site is located. This
should be the domain name only, without the "http://" or any
filename or folder information.
Login using a form on a web
page
Check this box if the web site uses an HTML form for logging in. Click
Login... to have dtSearch automatically
capture the settings used to login to this site.
Ask for password when
needed.
Check this box to have dtSearch prompt for a password when a site requires
you to log in. You will have to enter the password each time you
index the site, and dtSearch will not save your password information.
Username
Password
The username and password for this server. If you leave this
setting blank and check the Ask for password when needed box, then
dtSearch will ask for a username and password when it accesses the site,
if a password is needed. If you fill in a password, dtSearch
will remember the password so you can index or search on this server without
entering a password each time.
Note: Passwords are saved without encryption, so anyone who has access to your computer may be able to read them.