Using curl with a https proxy

curlhttpsPROXY

I have setup a squid proxy so that it listens on a HTTPS port instead of the usual HTTP port, in order to have encrypted communication between the client and the proxy itself.

While I have been able to configure other tools such as Firefox to use said proxy, I am unable to do the same with cURL. Regardless of how I set the proxy (environment variables, command line arguments…) cURL insists on trying to connect through plain HTTP.

Looking at cURL documentation for proxies, it seems that only SOCKS or plain HTTP is supported. Can anybody confirm this ? If so, there is any other similar tool that supports a proxy running on a HTTPS port ?

Best Answer

you have to wait some weeks, because this feature will be included in the next version which should be release on 21st of December https://daniel.haxx.se/blog/2016/11/26/https-proxy-with-curl/

Related Solutions

Setting Squid Transparent Proxy

The standard port for squid is 3128. It supports HTTP, HTTPS, and other protocols on this port. It also supports a transparent HTTP proxy mode using a separate port. For a transparent proxy to work, you will need NAT rules to forward web traffic to the proxy. I Setup a Squid Transparent Proxy using both ports.

There is no conflict with your Apache server on 80 and 443. Do review the configuration so that you don't cache your local server. Normally you should exempt connections to your local server from passing though the transparent proxy.

EDIT: To operate as a transparent proxy for your users you will need to configure your firewall to forward all web requests not originating from your squid server to the squid server. In iptables this is done with a DNAT configuration. I use shorewall to build my firewall and have a rule like this. ($SQUID resolves to the IP address of my squid server.)

HTTP(DNAT)        loc             dmz:$SQUID:3129  -      -    -   !192.168.0.0/16

You may also want to forward other ports commonly used for HTTP to squid. I forward the ports 81, 82, and 8080 among other to squid.

You may want to distribute your proxy configuration as I detailed in Setting up Squid Proxy on Ubuntu. This can handle HTTPS as well as HTTP.

What does it mean for proxy server to be of “HTTPS” type

A proxy can be both an HTTP proxy and an HTTPS proxy if it supports the CONNECT command. If it does not support the CONNECT command, it can only do HTTP.

During normal operation, the HTTP proxy receives the HTTP request, and is "smart enough" to understand it and so is able to optimize operations via methods such as searching its cache to serve the response without going to the destination server, or consulting a white-list/black-list to see if this URL is allowed, etc.

In CONNECT mode, none of this happens. The proxy establishes a TCP connection to the destination server, and simply forwards all traffic from the client to the destination server and all traffic from the destination server to the client. That means that any TCP protocol can work (HTTPS, SSH, FTP - even plain HTTP), as the proxy then becomes just a simple dumb pipe.

Best Answer

Related Solutions

Setting Squid Transparent Proxy

What does it mean for proxy server to be of “HTTPS” type

Related Question