Eric Workman

Curl's --connect-to

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For a long time I've used the curl command like

curl -kH 'Host: testingappnodea.internal'

to get a specific host behind a load balancer.

Today I've learned about curl's --connect-to <HOST1:PORT1:HOST2:PORT2> option.

For a request to the given HOST:PORT pair, connect to CONNECT-TO-HOST:CONNECT-TO-PORT 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. "host" and "port" may be the empty string, meaning "any host/port". "connect-to-host" and "connect-to-port" may also be the empty string, meaning "use the request's original host/port".

This option can be used many times to add many connect rules.

See also --resolve and -H, --header. Added in 7.49.0.

Now I use more explicit and straight-forward command

curl -k --connect-to testingappnodea.internal:443