[RHEL] Why I got messages "TCP_DENIED/407" into Squid logs when using "ntlm_auth" as authentication method ?

Solution Verified - Updated -


  • After install Squid and configure its authentication method to use "ntlm_auth", a lot of entries "TCP_DENIED/407" were found into Squid log files, but all Active Directory authentications were made without errors.
  • This configuration intends to make a single-sign-on available for Squid users.
  • A lot of lines as below can be found into /var/log/squid/access.log:

    268234226.935     0 TCP_DENIED/407 2117 CONNECT www.redhat.com:443 - NONE/- text/html


  • Red Hat Enterprise Linux all versions

  • Squid cache proxy using ntlm_auth to authenticate in Microsoft Active Directory

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