Watchguard V10 User Manual page 294

CHAPTER 10: Using Proxies
262
include systems running the Windows NT
operating system, and on stand-alone systems.
NTLM credentials are based on data obtained
during the interactive logon process and consist of
a domain name, a user name, and a one-way hash
of the user's password. NTLM uses an encrypted
challenge/response protocol to authenticate a user
without sending the user's password over the wire.
Instead, the system requesting authentication must
perform a calculation that proves it has access to
the secured NTLM credentials (Microsoft).
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