c: Copyright (C) Daniel Stenberg, , et al. SPDX-License-Identifier: curl Long: ntlm Help: Use HTTP NTLM authentication Mutexed: basic negotiate digest anyauth See-also: proxy-ntlm Protocols: HTTP Requires: TLS Category: auth http Example: --ntlm -u user:password $URL Added: 7.10.6 Multi: mutex --- Enables NTLM authentication. The NTLM authentication method was designed by Microsoft and is used by IIS web servers. It is a proprietary protocol, reverse-engineered by clever people and implemented in curl based on their efforts. This kind of behavior should not be endorsed, you should encourage everyone who uses NTLM to switch to a public and documented authentication method instead, such as Digest. If you want to enable NTLM for your proxy authentication, then use --proxy-ntlm. If this option is used several times, only the first one is used.