curl/docs/cmdline-opts/connect-to.d

c: Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Long: connect-to
Arg: <HOST1:PORT1:HOST2:PORT2>
Help: Connect to host
Added: 7.49.0
See-also: resolve header
Category: connection
Example: --connect-to example.com:443:example.net:8443 $URL
Multi: append
---

For a request to the given HOST1:PORT1 pair, connect to HOST2:PORT2 instead.
This option is suitable to direct requests at a specific server, e.g. at a
specific cluster node in a cluster of servers. This option is only used to
establish the network connection. It does NOT affect the hostname/port that is
used for TLS/SSL (e.g. SNI, certificate verification) or for the application
protocols. "HOST1" and "PORT1" may be the empty string, meaning "any
host/port". "HOST2" and "PORT2" may also be the empty string, meaning "use the
request's original host/port".

A "host" specified to this option is compared as a string, so it needs to
match the name used in request URL. It can be either numerical such as
"127.0.0.1" or the full host name such as "example.org".