CURLOPT_RESOLVE ignored when a proxy is set

[lessandro]

Setting up a proxy will cause CURLOPT_RESOLVE to be ignored.

This is especially problematic if you are relying on CURLOPT_RESOLVE to provide a host name for SNI or common name validation for a server without a reachable domain name.

For example, I want to connect to a server at https://192.168.1.100 and expect the common name "abcdef123456". This works fine with CURLOPT_RESOLVE -- adding abcdef123456:443:192.168.1.100 to the resolve list, and connecting to https://abcdef123456/, however when a proxy is set, curl sends a CONNECT abcdef123456:443 to the proxy, which will not work.

CURL: Added abcdef123456:443:192.168.1.100 to DNS cache
CURL: Hostname 192.168.1.200 was found in DNS cache
CURL:   Trying 192.168.1.200...
CURL: TCP_NODELAY set
CURL: Connected to 192.168.1.200 (192.168.1.200) port 10000 (#6)
CURL: allocate connect buffer!
CURL: Establish HTTP proxy tunnel to abcdef123456:443
CURL > CONNECT abcdef123456:443 HTTP/1.1
Host: abcdef123456:443
Proxy-Connection: Keep-Alive

CURL < HTTP/1.1 502 Fiddler - DNS Lookup Failed

I expect curl to send a CONNECT 192.168.1.100:443 to the proxy instead.

[bagder]

I can understand what you wanted to happen here, but when curl uses a HTTP proxy it doesn't try to resolve any name (that would even risk leaking that information to local servers) but will send the name as-is to the proxy. CURLOPT_RESOLVE shortcuts name resolving, but since it isn't done for HTTP proxies it has no effect when that's used. Thus, this is actually working as intended!

[bagder]

This seems to not be a bug.