1--- 2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. 3SPDX-License-Identifier: curl 4Long: proto 5Arg: <protocols> 6Help: Enable/disable PROTOCOLS 7Added: 7.20.2 8Category: connection curl 9Multi: single 10See-also: 11 - proto-redir 12 - proto-default 13Example: 14 - --proto =http,https,sftp $URL 15--- 16 17# `--proto` 18 19Limit what protocols to allow for transfers. Protocols are evaluated left to 20right, are comma separated, and are each a protocol name or 'all', optionally 21prefixed by zero or more modifiers. Available modifiers are: 22 23## + 24Permit this protocol in addition to protocols already permitted (this is 25the default if no modifier is used). 26 27## - 28Deny this protocol, removing it from the list of protocols already permitted. 29 30## = 31Permit only this protocol (ignoring the list already permitted), though 32subject to later modification by subsequent entries in the comma separated 33list. 34 35## 36 37For example: --proto -ftps uses the default protocols, but disables ftps 38 39--proto -all,https,+http only enables http and https 40 41--proto =http,https also only enables http and https 42 43Unknown and disabled protocols produce a warning. This allows scripts to 44safely rely on being able to disable potentially dangerous protocols, without 45relying upon support for that protocol being built into curl to avoid an error. 46 47This option can be used multiple times, in which case the effect is the same 48as concatenating the protocols into one instance of the option. 49
