CURLOPT_SOCKS5_AUTH(3) Library Functions Manual CURLOPT_SOCKS5_AUTH(3)
NAME
CURLOPT_SOCKS5_AUTH - methods for SOCKS5 proxy authentication
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SOCKS5_AUTH, long bitmask);
DESCRIPTION
Pass a long as parameter, which is set to a bitmask, to tell libcurl
which authentication method(s) are allowed for SOCKS5 proxy
authentication. The only supported flags are CURLAUTH_BASIC, which
allows username/password authentication, CURLAUTH_GSSAPI, which allows
GSS-API authentication, and CURLAUTH_NONE, which allows no
authentication. Set the actual username and password with the
CURLOPT_PROXYUSERPWD(3) option.
The specific socks authentication method is an access property, it does
not change the security context. This means that this option changes
how the connection and access to the proxy happens when a connection is
setup, but it does not affect which proxy connections libcurl can
reuse. libcurl may reuse a connection that was set up with a different
socks authentication method. Proxy connection reuse still depends on
other properties matching, such as the protocol, proxy hostname, port
number, credentials and other settings that affect the connection.
DEFAULT
CURLAUTH_BASIC | CURLAUTH_GSSAPI
PROTOCOLS
This functionality affects all supported protocols
EXAMPLE
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode result;
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
/* request to use a SOCKS5 proxy */
curl_easy_setopt(curl, CURLOPT_PROXY, "socks5://user:pass@myproxy.com");
/* enable username/password authentication only */
curl_easy_setopt(curl, CURLOPT_SOCKS5_AUTH, CURLAUTH_BASIC);
/* Perform the request */
result = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
HISTORY
CURLAUTH_* macros became long types in 7.26.0, prior to this version a
long cast was necessary when passed to curl_easy_setopt(3).
AVAILABILITY
Added in curl 7.55.0
RETURN VALUE
curl_easy_setopt(3) returns a CURLcode indicating success or error.
CURLE_OK (0) means everything was OK, non-zero means an error occurred,
see libcurl-errors(3).
SEE ALSO
CURLOPT_PROXY(3), CURLOPT_PROXYTYPE(3)
libcurl 2026-06-09 CURLOPT_SOCKS5_AUTH(3)
curl 8.20.0 - Generated Wed Jun 10 08:04:35 CDT 2026