Module ngx_stream_proxy_module

The ngx_stream_proxy_module module (1.9.0) allows proxying data streams over TCP, UDP (1.9.13), and UNIX-domain sockets.

server {
    listen 127.0.0.1:12345;
    proxy_pass 127.0.0.1:8080;
}

server {
    listen 12345;
    proxy_connect_timeout 1s;
    proxy_timeout 1m;
    proxy_pass example.com:12345;
}

server {
    listen 53 udp reuseport;
    proxy_timeout 20s;
    proxy_pass dns.example.com:53;
}

server {
    listen [::1]:12345;
    proxy_pass unix:/tmp/stream.socket;
}

Makes outgoing connections to a proxied server originate from the specified local IP address. Parameter value can contain variables (1.11.2). The special value off cancels the effect of the proxy_bind directive inherited from the previous configuration level, which allows the system to auto-assign the local IP address.

The transparent parameter (1.11.0) 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_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.

proxy_buffer_size 16k;

Sets the size of the buffer used for reading data from the proxied server. Also sets the size of the buffer used for reading data from the client.

proxy_connect_timeout 60s;

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

proxy_download_rate 0;

Limits the speed of reading the data from the proxied server. The rate is specified in bytes per second. The zero value disables rate limiting. The limit is set per a connection, so if nginx simultaneously opens two connections to the proxied server, the overall rate will be twice as much as the specified limit.

proxy_next_upstream on;

When a connection to the proxied server cannot be established, determines whether a client connection will be passed to the next server.

Passing a connection to the next server can be limited by the number of tries and by time.

proxy_next_upstream_timeout 0;

Limits the time allowed to pass a connection to the next server. The 0 value turns off this limitation.

proxy_next_upstream_tries 0;

Limits the number of possible tries for passing a connection to the next server. The 0 value turns off this limitation.

Sets the address of a proxied server. The address can be specified as a domain name or IP address, and a port:

proxy_pass localhost:12345;

or as a UNIX-domain socket path:

proxy_pass unix:/tmp/stream.socket;

If a domain name resolves to several addresses, all of them will be used in a round-robin fashion. In addition, an address can be specified as a server group.

The address can also be specified using variables (1.11.3):

proxy_pass $upstream;

In this case, the server name is searched among the described server groups, and, if not found, is determined using a resolver.

proxy_protocol off;

Enables the PROXY protocol for connections to a proxied server.

proxy_requests 0;

Sets the number of client datagrams at which binding between a client and existing UDP stream session is dropped. After receiving the specified number of datagrams, next datagram from the same client starts a new session. The session terminates when all client datagrams are transmitted to a proxied server and the expected number of responses is received, or when it reaches a timeout.

Sets the number of datagrams expected from the proxied server in response to a client datagram if the UDP protocol is used. The number serves as a hint for session termination. By default, the number of datagrams is not limited.

If zero value is specified, no response is expected. However, if a response is received and the session is still not finished, the response will be handled.

proxy_socket_keepalive off;

Configures the “TCP keepalive” behavior for outgoing connections to a proxied server. By default, the operating system’s settings are in effect for the socket. If the directive is set to the value “on”, the SO_KEEPALIVE socket option is turned on for the socket.

proxy_ssl off;

Enables the SSL/TLS protocol for connections to a proxied server.

Specifies a file with the certificate in the PEM format used for authentication to a proxied server.

Specifies a file with the secret key in the PEM format used for authentication to a proxied server.

proxy_ssl_ciphers DEFAULT;

Specifies the enabled ciphers for connections to a proxied server. The ciphers are specified in the format understood by the OpenSSL library.

The full list can be viewed using the “openssl ciphers” command.

Specifies a file with revoked certificates (CRL) in the PEM format used to verify the certificate of the proxied server.

proxy_ssl_name host from proxy_pass;

Allows overriding the server name used to verify the certificate of the proxied server and to be passed through SNI when establishing a connection with the proxied server. The server name can also be specified using variables (1.11.3).

By default, the host part of the proxy_pass address is used.

Specifies a file with passphrases for secret keys where each passphrase is specified on a separate line. Passphrases are tried in turn when loading the key.

proxy_ssl_protocols TLSv1 TLSv1.1 TLSv1.2;

Enables the specified protocols for connections to a proxied server.

proxy_ssl_server_name off;

Enables or disables passing of the server name through TLS Server Name Indication extension (SNI, RFC 6066) when establishing a connection with the proxied server.

proxy_ssl_session_reuse on;

Determines whether SSL sessions can be reused when working with the proxied server. If the errors “SSL3_GET_FINISHED:digest check failed” appear in the logs, try disabling session reuse.

Specifies a file with trusted CA certificates in the PEM format used to verify the certificate of the proxied server.

proxy_ssl_verify off;

Enables or disables verification of the proxied server certificate.

proxy_ssl_verify_depth 1;

Sets the verification depth in the proxied server certificates chain.

proxy_timeout 10m;

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_upload_rate 0;

Limits the speed of reading the data from the client. The rate is specified in bytes per second. The zero value disables rate limiting. The limit is set per a connection, so if the client simultaneously opens two connections, the overall rate will be twice as much as the specified limit.