name

This module provides support for the CONNECT method request. This method is mainly used to tunnel SSL requests through proxy servers.

Table of Contents

• name
• Example
  • configuration example
    • example for curl
  • configuration example for CONNECT request in https
    • example for curl (CONNECT request in https)
    • example for browser
  • example for basic authentication
  • example for proxying WebSocket
• Install
  • select patch
  • build nginx
    • build as a dynamic module
  • build OpenResty
• Test Suite
• Error Log
• Directive
  • proxy_connect
  • proxy_connect_allow
  • proxy_connect_connect_timeout
  • proxy_connect_data_timeout
  • proxy_connect_read_timeout(deprecated)
  • proxy_connect_send_timeout(deprecated)
  • proxy_connect_address
  • proxy_connect_bind
  • proxy_connect_response
• Variables
  • $connect_host
  • $connect_port
  • $connect_addr
  • $proxy_connect_connect_timeout
  • $proxy_connect_data_timeout
  • $proxy_connect_read_timeout(deprecated)
  • $proxy_connect_send_timeout(deprecated)
  • $proxy_connect_resolve_time
  • $proxy_connect_connect_time
  • $proxy_connect_first_byte_time
  • $proxy_connect_response
• Compatibility
  • Nginx Compatibility
  • OpenResty Compatibility
  • Tengine Compatibility
• FAQ
• Known Issues
• See Also
• Author
• License

Example

Configuration Example

server {
    listen                         3128;

    # dns resolver used by forward proxying
    resolver                       8.8.8.8;

    # forward proxy for CONNECT requests
    proxy_connect;
    proxy_connect_allow            443 563;
    proxy_connect_connect_timeout  10s;
    proxy_connect_data_timeout     10s;

    # defined by yourself for non-CONNECT requests
    # Example: reverse proxy for non-CONNECT requests
    location / {
        proxy_pass http://$host;
        proxy_set_header Host $host;
    }
}

• The resolver directive MUST be configured globally in server {} block (or http {} block).
• Any location {} block, upstream {} block and any other standard backend/upstream directives, such as proxy_pass, do not impact the functionality of this module. (The proxy_connect module only executes the logic for requests that use the CONNECT method and that have a data flow under this tunnel.)
  • If you dont want to handle non-CONNECT requests, you can modify location {} block as following:

    location / {
        return 403 "Non-CONNECT requests are forbidden";
    }
    

Example for curl

With above configuration(configuration example ), you can get any https website via HTTP CONNECT tunnel. A simple test with command curl is as following:

$ curl https://github.com/ -v -x 127.0.0.1:3128
*   Trying 127.0.0.1...                                           -.
* Connected to 127.0.0.1 (127.0.0.1) port 3128 (#0)                | curl creates TCP connection with nginx (with proxy_connect module).
* Establish HTTP proxy tunnel to github.com:443                   -'
> CONNECT github.com:443 HTTP/1.1                                 -.
> Host: github.com:443                                         (1) | curl sends CONNECT request to create tunnel.
> User-Agent: curl/7.43.0                                          |
> Proxy-Connection: Keep-Alive                                    -'
>
< HTTP/1.0 200 Connection Established                             .- nginx replies 200 that tunnel is established.
< Proxy-agent: nginx                                           (2)|  (The client is now being proxied to the remote host. Any data sent
<                                                                 '-  to nginx is now forwarded, unmodified, to the remote host)

* Proxy replied OK to CONNECT request
* TLS 1.2 connection using TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256  -.
* Server certificate: github.com                                   |
* Server certificate: DigiCert SHA2 Extended Validation Server CA  | curl sends "https://github.com" request via tunnel,
* Server certificate: DigiCert High Assurance EV Root CA           | proxy_connect module will proxy data to remote host (github.com).
> GET / HTTP/1.1                                                   |
> Host: github.com                                             (3) |
> User-Agent: curl/7.43.0                                          |
> Accept: */*                                                     -'
>
< HTTP/1.1 200 OK                                                 .-
< Date: Fri, 11 Aug 2017 04:13:57 GMT                             |
< Content-Type: text/html; charset=utf-8                          |  Any data received from remote host will be sent to client
< Transfer-Encoding: chunked                                      |  by proxy_connect module.
< Server: GitHub.com                                           (4)|
< Status: 200 OK                                                  |
< Cache-Control: no-cache                                         |
< Vary: X-PJAX                                                    |
...                                                               |
... <other response headers & response body> ...                  |
...                                                               '-

The sequence diagram of above example is as following:

  curl                     nginx (proxy_connect)            github.com
    |                             |                          |
(1) |-- CONNECT github.com:443 -->|                          |
    |                             |                          |
    |                             |----[ TCP connection ]--->|
    |                             |                          |
(2) |<- HTTP/1.1 200           ---|                          |
    |   Connection Established    |                          |
    |                             |                          |
    |                                                        |
    ========= CONNECT tunnel has been established. ===========
    |                                                        |
    |                             |                          |
    |                             |                          |
    |   [ SSL stream       ]      |                          |
(3) |---[ GET / HTTP/1.1   ]----->|   [ SSL stream       ]   |
    |   [ Host: github.com ]      |---[ GET / HTTP/1.1   ]-->.
    |                             |   [ Host: github.com ]   |
    |                             |                          |
    |                             |                          |
    |                             |                          |
    |                             |   [ SSL stream       ]   |
    |   [ SSL stream       ]      |<--[ HTTP/1.1 200 OK  ]---'
(4) |<--[ HTTP/1.1 200 OK  ]------|   [ < html page >    ]   |
    |   [ < html page >    ]      |                          |
    |                             |                          |

configuration example for CONNECT request in HTTPS

server {
    listen                         3128 ssl;

    # self signed certificate generated via openssl command
    ssl_certificate_key            /path/to/server.key;
    ssl_certificate                /path/to/server.crt;
    ssl_session_cache              shared:SSL:1m;

    # dns resolver used by forward proxying
    resolver                       8.8.8.8;

    # forward proxy for CONNECT request
    proxy_connect;
    proxy_connect_allow            443 563;
    proxy_connect_connect_timeout  10s;
    proxy_connect_data_timeout     10s;

    # defined by yourself for non-CONNECT request
    # Example: reverse proxy for non-CONNECT requests
    location / {
        proxy_pass http://$host;
        proxy_set_header Host $host;
    }
}

example for curl (CONNECT request in https)

With above configuration(configuration example for CONNECT request in https), you can get any https website via HTTPS CONNECT tunnel(CONNECT request in https). A simple test with command curl is as following:

Tips on using curl command:

• -x https://... makes curl send CONNECT request in https.
• --proxy-insecure disables ssl signature verification for ssl connection established with nginx proxy_connect server(https://localhost:3128), but it does not disable verification with proxied backend server(https://nginx.org in the example below).
  • If you want to disable signature verfication with proxied backend server, you can use -k option.

$ curl https://nginx.org/ -sv -o/dev/null -x https://localhost:3128 --proxy-insecure
*   Trying 127.0.0.1:3128...
* TCP_NODELAY set
* Connected to localhost (127.0.0.1) port 3128 (#0)
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
  CApath: /etc/ssl/certs
} [5 bytes data]
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
} [512 bytes data]
* TLSv1.3 (IN), TLS handshake, Server hello (2):
{ [112 bytes data]
* TLSv1.2 (IN), TLS handshake, Certificate (11):
{ [799 bytes data]
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
{ [300 bytes data]
* TLSv1.2 (IN), TLS handshake, Server finished (14):
{ [4 bytes data]
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
} [37 bytes data]
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
} [1 bytes data]
* TLSv1.2 (OUT), TLS handshake, Finished (20):
} [16 bytes data]
* TLSv1.2 (IN), TLS handshake, Finished (20):
{ [16 bytes data]
* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
* ALPN, server accepted to use http/1.1
* Proxy certificate:
*  subject: C=AU; ST=Some-State; O=Internet Widgits Pty Ltd
*  start date: Nov 25 08:36:38 2022 GMT
*  expire date: Nov 25 08:36:38 2023 GMT
*  issuer: C=AU; ST=Some-State; O=Internet Widgits Pty Ltd
*  SSL certificate verify result: self signed certificate (18), continuing anyway.
* allocate connect buffer!
* Establish HTTP proxy tunnel to nginx.org:443
} [5 bytes data]
> CONNECT nginx.org:443 HTTP/1.1
> Host: nginx.org:443
> User-Agent: curl/7.68.0
> Proxy-Connection: Keep-Alive
>
{ [5 bytes data]
< HTTP/1.1 200 Connection Established
< Proxy-agent: nginx
<
* Proxy replied 200 to CONNECT request
* CONNECT phase completed!
* ALPN, offering h2
* ALPN, offering http/1.1
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
  CApath: /etc/ssl/certs
} [5 bytes data]
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
} [512 bytes data]
* CONNECT phase completed!
* CONNECT phase completed!
{ [5 bytes data]
* TLSv1.3 (IN), TLS handshake, Server hello (2):
{ [80 bytes data]
* TLSv1.2 (IN), TLS handshake, Certificate (11):
{ [2749 bytes data]
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
{ [300 bytes data]
* TLSv1.2 (IN), TLS handshake, Server finished (14):
{ [4 bytes data]
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
} [37 bytes data]
* TLSv1.2 (OUT), TLS change cipher, Change cipher spec (1):
} [1 bytes data]
* TLSv1.2 (OUT), TLS handshake, Finished (20):
} [16 bytes data]
* TLSv1.2 (IN), TLS handshake, Finished (20):
{ [16 bytes data]
* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
* ALPN, server accepted to use http/1.1
* Server certificate:
*  subject: CN=nginx.org
*  start date: Dec  9 15:29:31 2022 GMT
*  expire date: Mar  9 15:29:30 2023 GMT
*  subjectAltName: host "nginx.org" matched cert's "nginx.org"
*  issuer: C=US; O=Let's Encrypt; CN=R3
*  SSL certificate verify ok.
} [5 bytes data]
> GET / HTTP/1.1
> Host: nginx.org
> User-Agent: curl/7.68.0
> Accept: */*
>
{ [5 bytes data]
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Server: nginx/1.21.5
< Date: Mon, 06 Mar 2023 06:05:24 GMT
< Content-Type: text/html; charset=utf-8
< Content-Length: 7488
< Last-Modified: Tue, 28 Feb 2023 21:07:43 GMT
< Connection: keep-alive
< Keep-Alive: timeout=15
< ETag: "63fe6d1f-1d40"
< Accept-Ranges: bytes
<
{ [7488 bytes data]
* Connection #0 to host localhost left intact

Example for browser

You can configure your browser to use this nginx as PROXY server.

• Google Chrome HTTPS PROXY SETTING: guide & config for how to configure this module working under SSL layer.

Example for Basic Authentication

We can do access control on CONNECT request using nginx auth basic module.
See this guide for more details.

Example for proxying WebSocket

• Note that nginx has its own WebSocket reverse proxy module, which is is not limited to the CONNECT tunnel, see nginx.org doc: Nginx WebSocket proxying and nginx.com blog: NGINX as a WebSocket Proxy.
• This module enables the WebSocket protocol to work over the CONNECT tunnel, see #267 (comment)

Install

Select patch

• Select right patch for building:
• All patch files have been included in patch/ directory of this module. You dont need to download the patch directly from web page.

• proxy_connect_<VERSION>.patch disables nginx REWRITE phase for CONNECT request by default, which means if, set, rewrite_by_lua and other REWRITE phase directives cannot be used.
• proxy_connect_rewrite_<VERSION>.patch enables these REWRITE phase directives.

Build nginx

• Build nginx with this module from source:

$ wget http://nginx.org/download/nginx-1.9.2.tar.gz
$ tar -xzvf nginx-1.9.2.tar.gz
$ cd nginx-1.9.2/
$ patch -p1 < /path/to/ngx_http_proxy_connect_module/patch/proxy_connect.patch
$ ./configure --add-module=/path/to/ngx_http_proxy_connect_module
$ make && make install

Build as a dynamic module

• Starting from nginx 1.9.11, you can also compile this module as a dynamic module, by using the --add-dynamic-module=PATH option instead of --add-module=PATH on the ./configure command line.

$ wget http://nginx.org/download/nginx-1.9.12.tar.gz
$ tar -xzvf nginx-1.9.12.tar.gz
$ cd nginx-1.9.12/
$ patch -p1 < /path/to/ngx_http_proxy_connect_module/patch/proxy_connect.patch
$ ./configure --add-dynamic-module=/path/to/ngx_http_proxy_connect_module
$ make && make install

• And then you can explicitly load the module in your nginx.conf via the load_module directive, for example,

load_module /path/to/modules/ngx_http_proxy_connect_module.so;

• ❗ Note that the ngx_http_proxy_connect_module.so file MUST be loaded by nginx binary that is compiled with the .so file at the same time.

Build OpenResty

• Build OpenResty with this module from source:

$ wget https://openresty.org/download/openresty-1.19.3.1.tar.gz
$ tar -zxvf openresty-1.19.3.1.tar.gz
$ cd openresty-1.19.3.1
$ ./configure --add-module=/path/to/ngx_http_proxy_connect_module
$ patch -d build/nginx-1.19.3/ -p 1 < /path/to/ngx_http_proxy_connect_module/patch/proxy_connect_rewrite_101504.patch
$ make && make install

Test Suite

• To run the whole test suite:

$ hg clone http://hg.nginx.org/nginx-tests/

# If you use latest lua-nginx-module that needs lua-resty-core and
# lua-resty-lrucache, you should add "lua_package_path ...;" directive
# into nginx.conf of test cases. You can use the following command:
#
# $ export TEST_NGINX_GLOBALS_HTTP='lua_package_path "/path/to/nginx/lib/lua/?.lua;;";'

$ export TEST_NGINX_BINARY=/path/to/nginx/binary
$ prove -v -I /path/to/nginx-tests/lib /path/to/ngx_http_proxy_connect_module/t/

• For the complete process of building and testing this module, see:
  • workflow files: here
  • runs from all workflows: here

Error Log

This module logs its own error message beginning with "proxy_connect:" string.
Some typical error logs are shown as following:

• The proxy_connect module tries to establish tunnel connection with backend server, but the TCP connection timeout occurs.

2019/08/07 17:27:20 [error] 19257#0: *1 proxy_connect: upstream connect timed out (peer:216.58.200.4:443) while connecting to upstream, client: 127.0.0.1, server: , request: "CONNECT www.google.com:443 HTTP/1.1", host: "www.google.com:443"

Directive

proxy_connect

Syntax: proxy_connect
Default: none
Context: server

Enable "CONNECT" HTTP method support.

proxy_connect_allow

Syntax: proxy_connect_allow all | [port ...] | [port-range ...]
Default: 443 563
Context: server

This directive specifies a list of port numbers or ranges to which the proxy CONNECT method may connect.
By default, only the default https port (443) and the default snews port (563) are enabled.
Using this directive will override this default and allow connections to the listed ports only.

The value all will allow all ports to proxy.

The value port will allow specified port to proxy.

The value port-range will allow specified range of port to proxy, for example:

proxy_connect_allow 1000-2000 3000-4000; # allow range of port from 1000 to 2000, from 3000 to 4000.

proxy_connect_connect_timeout

Syntax: proxy_connect_connect_timeout time
Default: none
Context: server

Defines a timeout for establishing a connection with a proxied server.

proxy_connect_data_timeout

Syntax: proxy_connect_data_timeout time
Default: 60s
Context: server

Sets the timeout between two successive read or write operations on client or proxied server connections. If no data is transmitted within this time, the connection is closed.

proxy_connect_read_timeout

Syntax: proxy_connect_read_timeout time
Default: 60s
Context: server

Deprecated.

It has the same function as the directive proxy_connect_data_timeout for compatibility. You can configure only one of the directives (proxy_connect_data_timeout or proxy_connect_read_timeout).

proxy_connect_send_timeout

Syntax: proxy_connect_send_timeout time
Default: 60s
Context: server

Deprecated.

It has no function.

proxy_connect_address

Syntax: proxy_connect_address address | off
Default: none
Context: server

Specifiy an IP address of the proxied server. The address can contain variables.
The special value off is equal to none, which uses the IP address resolved from host name of CONNECT request line.

NOTE: If using set $<nginx variable> and proxy_connect_address $<nginx variable> together, you should use proxy_connect_rewrite.patch instead, see Install for more details.

proxy_connect_bind

Syntax: proxy_connect_bind address [transparent] | off
Default: none
Context: server

Makes outgoing connections to a proxied server originate from the specified local IP address with an optional port.
Parameter value can contain variables. The special value off is equal to none, which allows the system to auto-assign the local IP address and port.

The transparent parameter allows outgoing connections to a proxied server originate from a non-local IP address, for example, from a real IP address of a client:

proxy_connect_bind $remote_addr transparent;

In order for this parameter to work, it is usually necessary to run nginx worker processes with the superuser privileges. On Linux it is not required (1.13.8) as if the transparent parameter is specified, worker processes inherit the CAP_NET_RAW capability from the master process. It is also necessary to configure kernel routing table to intercept network traffic from the proxied server.

NOTE: If using set $<nginx variable> and proxy_connect_bind $<nginx variable> together, you should use proxy_connect_rewrite.patch instead, see Install for more details.

proxy_connect_response

Syntax: proxy_connect_response CONNECT response
Default: HTTP/1.1 200 Connection Established\r\nProxy-agent: nginx\r\n\r\n
Context: server

Set the response of CONNECT request.

Note that it is only used for CONNECT request, it cannot modify the data flow over CONNECT tunnel.

For example:

proxy_connect_response "HTTP/1.1 200 Connection Established\r\nProxy-agent: nginx\r\nX-Proxy-Connected-Addr: $connect_addr\r\n\r\n";

The curl command test case with above config is as following:

$ curl https://github.com -sv -x localhost:3128
* Connected to localhost (127.0.0.1) port 3128 (#0)
* allocate connect buffer!
* Establish HTTP proxy tunnel to github.com:443
> CONNECT github.com:443 HTTP/1.1
> Host: github.com:443
> User-Agent: curl/7.64.1
> Proxy-Connection: Keep-Alive
>
< HTTP/1.1 200 Connection Established            --.
< Proxy-agent: nginx                               | custom CONNECT response
< X-Proxy-Connected-Addr: 13.229.188.59:443      --'
...

Variables

$connect_host

host name from CONNECT request line.

$connect_port

port from CONNECT request line.

$connect_addr

IP address and port of the remote host, e.g. "192.168.1.5:12345". IP address is resolved from host name of CONNECT request line.

$proxy_connect_connect_timeout

Get or set timeout of proxy_connect_connect_timeout directive.

For example:

# Set default value

proxy_connect_connect_timeout   10s;
proxy_connect_data_timeout      10s;

# Overlap default value

if ($host = "test.com") {
    set $proxy_connect_connect_timeout  "10ms";
    set $proxy_connect_data_timeout     "10ms";
}

$proxy_connect_data_timeout

Get or set a timeout of proxy_connect_data_timeout directive.

$proxy_connect_read_timeout

Deprecated. It still can get or set a timeout of proxy_connect_data_timeout directive for compatibility.

$proxy_connect_send_timeout

Deprecated. It has no function.

$proxy_connect_resolve_time

Keeps time spent on name resolving; the time is kept in seconds with millisecond resolution.

• Value of "" means this module does not work on this request.
• Value of "-" means name resolving failed.

$proxy_connect_connect_time

Keeps time spent on establishing a connection with the upstream server; the time is kept in seconds with millisecond resolution.

• Value of "" means this module does not work on this request.
• Value of "-" means name resolving or connecting failed.

$proxy_connect_first_byte_time

Keeps time to receive the first byte of data from the upstream server; the time is kept in seconds with millisecond resolution.

• Value of "" means this module does not work on this request.
• Value of "-" means name resolving, connecting or receving failed.

$proxy_connect_response

Get or set the response of CONNECT request.
The default response of CONNECT request is "HTTP/1.1 200 Connection Established\r\nProxy-agent: nginx\r\n\r\n".

Note that it is only used for CONNECT request, it cannot modify the data flow over CONNECT tunnel.

For example:

# modify default Proxy-agent header
set $proxy_connect_response "HTTP/1.1 200\r\nProxy-agent: nginx/1.19\r\n\r\n";

The variable value does not support nginx variables. You can use lua-nginx-module to construct string that contains nginx variable. For example:

# The CONNECT response may be "HTTP/1.1 200\r\nProxy-agent: nginx/1.19.6\r\n\r\n"

rewrite_by_lua '
    ngx.var.proxy_connect_response =
      string.format("HTTP/1.1 200\\r\\nProxy-agent: nginx/%s\\r\\n\\r\\n", ngx.var.nginx_version)
';

Also note that set or rewrite_by_lua* directive is run during the REWRITE phase, which is ahead of dns resolving phase. It cannot get right value of some variables, for example, $connect_addr value is nil. In such case, you should use proxy_connect_response directive instead.

Compatibility

Nginx Compatibility

The latest module is compatible with the following versions of nginx:

• 1.25.0 (mainline version of 1.25.x)
• 1.24.0 (version of 1.24.x)
• 1.22.1 (version of 1.22.x)
• 1.20.2 (version of 1.20.x)
• 1.18.0 (version of 1.18.x)
• 1.16.1 (version of 1.16.x)
• 1.14.2 (version of 1.14.x)
• 1.12.1 (version of 1.12.x)
• 1.10.3 (version of 1.10.x)
• 1.8.1 (version of 1.8.x)
• 1.6.3 (version of 1.6.x)
• 1.4.7 (version of 1.4.x)

OpenResty Compatibility

The latest module is compatible with the following versions of OpenResty:

• 1.21.4 (version: 1.21.4.2 RC1)
• 1.19.3 (version: 1.19.3.1)
• 1.17.8 (version: 1.17.8.2)
• 1.15.8 (version: 1.15.8.1)
• 1.13.6 (version: 1.13.6.2)

Tengine Compatibility

This module has been integrated into Tengine 2.3.0.

• Tengine ngx_http_proxy_connect_module documentation
• Merged pull request for Tengine 2.3.0.

FAQ

See FAQ page.

Known Issues

• In HTTP/2, the CONNECT method is not supported. It only supports the CONNECT method request in HTTP/1.x and HTTPS.

See Also

• HTTP tunnel - Wikipedia
• CONNECT method in HTTP/1.1
• CONNECT method in HTTP/2

Author

• Peng Qi: original author. He contributed this module to Tengine in this pull request.
• Xiaochen Wang: current maintainer. Rebuild this module for nginx.

LICENSE

See LICENSE for details.