Chapter 3 Authentication for FortiOS 5.0 : Configuring authenticated access : Authentication in security policies : NTLM authentication : NTLM guest access - CLI
  
NTLM guest access - CLI
Guest profile access may be granted to users failing NTLM authentication, such as visitors who have no user credentials on the network. To allow guest users in NTLM, use the following CLI command:
config firewall policy
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set action accept
set identity-based enable
set ntlm enable
set ntlm-guest enable
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