curl -H "Host: abc.example.com" 18.104.22.168
curl --resolve abc.example.com:80:22.214.171.124 http://abc.example.com
This is quiet handy. And in unfortunate circumstances one can need that but behind a proxy. So I was banging my head to understand how to do it. Eventually I resorted to looking at rfc2068.
The news are not good (as much as probably very little people care) - there is no way to perform that hack over a standard HTTP Proxy. Here's and excerpt:
There are two ways to ask a HTTP proxy to perform a request:5.2 The Resource Identified by a Request HTTP/1.1 origin servers SHOULD be aware that the exact resource identified by an Internet request is determined by examining both the Request-URI and the Host header field. An origin server that does not allow resources to differ by the requested host MAY ignore the Host header field value. (But see section 19.5.1 for other requirements on Host support in HTTP/1.1.) An origin server that does differentiate resources based on the host requested (sometimes referred to as virtual hosts or vanity hostnames) MUST use the following rules for determining the requested resource on an HTTP/1.1 request: 1. If Request-URI is an absoluteURI, the host is part of the Request-URI. Any Host header field value in the request MUST be ignored. 2. If the Request-URI is not an absoluteURI, and the request includes a Host header field, the host is determined by the Host header field value. 3. If the host as determined by rule 1 or 2 is not a valid host on the server, the response MUST be a 400 (Bad Request) error message. Recipients of an HTTP/1.0 request that lacks a Host header field MAY attempt to use heuristics (e.g., examination of the URI path for something unique to a particular host) in order to determine what exact resource is being requested.
GET http://abc.ecample.com/ HTTP 1.0or
GET / HTTP 1.0In the first form (point #1 above), even if `Host` header is provided, the proxy server must ignore it and send to the target web server whatever host is provided in the absolute URL. That's why it's technically impossible to do this over a HTTP proxy.
This doesn't mean you can't do it with a socks server or if proxy allows CONNECT to the desired destination port.
With socks perhaps `curl` should do just fine (haven't tested). Using CONNECT to port 80 though would require manual interaction with the socket or a little programming as standard tools would not use CONNECT for simple non-encrypted HTTP connections.
Here's how to use proxy with auth via telnet:
And here's a good example how to use the CONNECT method manually: