It seems KeepSolid’s servers run Squid (https://18.104.22.168:3129), and that the Firefox plugin somehow authenticates, so that Firefox can use it.
I want to use
curl with KeepSolid’s servers (aka. VPN Unlimited).
(Analyticshub.link seems to be the CN of the TLS certificate).
$ curl -v --proxy https://analyticshub.link:3129 --proxy-digest --proxy-user $user:$pass --location https://www.google.com/
* Trying 22.214.171.124:3129... * TCP_NODELAY set * Connected to analyticshub.link (126.96.36.199) port 3129 (#0) * ALPN, offering http/1.1 * successfully set certificate verify locations: * CAfile: /etc/ssl/certs/ca-certificates.crt CApath: /etc/ssl/certs * TLSv1.3 (OUT), TLS handshake, Client hello (1): * TLSv1.3 (IN), TLS handshake, Server hello (2): * TLSv1.2 (IN), TLS handshake, Certificate (11): * TLSv1.2 (IN), TLS handshake, Server key exchange (12): * TLSv1.2 (IN), TLS handshake, Server finished (14): * TLSv1.2 (OUT), TLS handshake, Client key exchange (16): * TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1): * TLSv1.2 (OUT), TLS handshake, Finished (20): * TLSv1.2 (IN), TLS handshake, Finished (20): * SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384 * ALPN, server did not agree to a protocol * Proxy certificate: * subject: CN=analyticshub.link * start date: Jul 5 08:11:25 2021 GMT * expire date: Oct 3 08:11:24 2021 GMT * subjectAltName: host "analyticshub.link" matched cert's "analyticshub.link" * issuer: C=US; O=Let's Encrypt; CN=R3 * SSL certificate verify ok. * allocate connect buffer! * Establish HTTP proxy tunnel to www.google.com:443 * Proxy auth using Digest with user 'firstname.lastname@example.org' > CONNECT www.google.com:443 HTTP/1.1 > Host: www.google.com:443 > User-Agent: curl/7.68.0 > Proxy-Connection: Keep-Alive > < HTTP/1.1 407 Proxy Authentication Required < Server: squid/3.5.23 < Mime-Version: 1.0 < Date: Sun, 01 Aug 2021 19:02:51 GMT < Content-Type: text/html;charset=utf-8 < Content-Length: 3557 < X-Squid-Error: ERR_CACHE_ACCESS_DENIED 0 < Vary: Accept-Language < Content-Language: en < Proxy-Authenticate: Basic realm="Web-Proxy" < X-Cache: MISS from vpnunlimitedapp.com < X-Cache-Lookup: NONE from vpnunlimitedapp.com:4129 < Connection: close < * Ignore 3557 bytes of response-body * Received HTTP code 407 from proxy after CONNECT * CONNECT phase completed! * Closing connection 0 curl: (56) Received HTTP code 407 from proxy after CONNECT
As you can see the above does not work. What should I do instead?