Nginx Wiki (outdated latest: http://nginxorg/en/docs/)

SynopsisThis module makes it possible to transfer requests to another server.Example:

<span>location</span> / <span>{</span>
  proxy_pass        <span>http</span>://localhost:<span>8000</span><span>;</span>
  proxy_set_header  X-Real-IP  <span>$remote_addr</span><span>;</span><span>}</span>

Note that when using the HTTP Proxy Module (or even when using FastCGI), the entire client request will be buffered in nginx before being passed on to the backend proxied servers. As a result, upload progress meters will not function correctly if they work by measuring the data received by the backend servers.Directivesproxy_bindsyntax: proxy_bind addressdefault: nonecontext: http, server, locationversion: ≥ 0.8.22example:

proxy_bind  192.168.1.1<span>;</span>

This directive binds each upstream socket to a local address before calling connect(). It may be useful if host has several interfaces/aliases and you want to pass outgoing connections from specific interface/address.proxy_buffer_size Syntax: proxy_buffer_size size Default: 4k|8k Context: http
server
location Reference: proxy_buffer_size
This directive set the buffer size, into which will be read the first part of the response, obtained from the proxied server.In this part of response the small response-header is located, as a rule.By default, the buffer size is equal to the size of one buffer in directive proxy_buffers; however, it is possible to set it to less.proxy_buffering Syntax: proxy_buffering on | off Default: on Context: http
server
location Reference: proxy_buffering
This directive activate response buffering of the proxied server.If buffering is activated, then nginx reads the answer from the proxied server as fast as possible, saving it in the buffer as configured by directives proxy_buffer_size and proxy_buffers. If the response does not fit into memory, then parts of it will be written to disk.If buffering is switched off, then the response is synchronously transferred to client immediately as it is received. nginx does not attempt to read the entire answer from the proxied server, the maximum size of data which nginx can accept from the server is set by directive proxy_buffer_size.Also note that caching upstream proxy responses won't work if proxy_buffering is set to off.For Comet applications based on long-polling it is important to set proxy_buffering to off, otherwise the asynchronous response is buffered and the Comet does not work.Buffering can be set on a per-request basis by setting the X-Accel-Buffering header in the proxy response.proxy_buffers Syntax: proxy_buffers number size Default: 8 4k|8k Context: http
server
location Reference: proxy_buffers
This directive sets the number and the size of buffers, into which will be read the answer, obtained from the proxied server. By default, the size of one buffer is equal to the size of page. Depending on platform this is either 4K or 8K.proxy_busy_buffers_size Syntax: proxy_busy_buffers_size size Default: 8k|16k Context: http
server
location Reference: proxy_busy_buffers_size
proxy_cache Syntax: proxy_cache zone | off Default: off Context: http
server
location Reference: proxy_cache
This directive sets name of zone for caching. The same zone can be used in multiple places.The cache honors backend's "Expires", "Cache-Control: no-cache", and "Cache-Control: max-age=XXX" headers since version 0.7.48. Since version 7.66, "private" and "no-store" are also honored. nginx does not handle "Vary" headers when caching. In order to ensure private items are not served to all users unintentionally by the cache, the back-end can set "no-cache" or "max-age=0", or the proxy_cache_key must include user-specific data such as $cookie_xxx. However, using cookie values as part of proxy_cache_key can defeat the benefits of caching for public items, so separate locations with different proxy_cache_key values might be necessary to separate private and public items.The cache depends on proxy buffers, and will not work if proxy_buffers is set to off.The following response headers flag a response as uncacheable unless they are ignored:

Set-Cookie

Cache-Control containing "no-cache", "no-store", "private", or a "max-age" with a non-numeric or 0 value

Expires with a time in the past

X-Accel-Expires: 0

proxy_cache_bypass Syntax: proxy_cache_bypass string ... Default:   Context: http
server
location Reference: proxy_cache_bypass
The directive specifies the conditions under which the answer will not be taken from the cache. If at least one of a string variable is not empty and not equal to "0", the answer is not taken from the cache:

 proxy_cache_bypass <span>$cookie_nocache</span><span>$arg_nocache</span><span>$arg_comment</span><span>;</span>
 proxy_cache_bypass <span>$http_pragma</span><span>$http_authorization</span><span>;</span>

Note that the response from the back-end is still eligible for caching. Thus one way of refreshing an item in the cache is sending a request with a header you pick yourself, e.g. "My-Secret-Header: 1", then having a proxy_cache_bypass line like:

proxy_cache_bypass <span>$http_my_secret_header</span><span>;</span>

Can be used in conjunction with the directive proxy_no_cache.proxy_cache_key Syntax: proxy_cache_key string Default: $scheme$proxy_host$request_uri Context: http
server
location Reference: proxy_cache_key
The directive specifies what information is included in the key for caching, for example

proxy_cache_key <span>"$host$request_uri$cookie_user"</span><span>;</span>

Note that by default, the hostname of the server is not included in the cache key. If you are using subdomains for different locations on your website, you need to include it, e.g. by changing the cache key to something like

proxy_cache_key <span>"$scheme$host$request_uri"</span><span>;</span>

proxy_cache_lock Syntax: proxy_cache_lock on | off Default: off Context: http
server
location Appeared in: 1.1.12 Reference: proxy_cache_lock When enabled, only one request at a time will be allowed to populate a new cache element identified according to the proxy_cache_key directive by passing a request to a proxied server. Other requests of the same cache element will either wait for a response to appear in the cache or the cache lock for this element to be released, up to the time set by the proxy_cache_lock_timeout directive. Similar effect for updating cache entry (this directive works only for inserting new cache element) can be archieved by using proxy_cache_use_stale updating directive.proxy_cache_lock_timeout Syntax: proxy_cache_lock_timeout time Default: 5s Context: http
server
location Appeared in: 1.1.12 Reference: proxy_cache_lock_timeout
proxy_cache_methodssyntax: proxy_cache_methods [GET HEAD POST];default: proxy_cache_methods GET HEAD;context: http, server, locationGET/HEAD is syntax sugar, i.e. you can not disable GET/HEAD even if you set just

proxy_cache_methods POST<span>;</span>

proxy_cache_min_uses Syntax: proxy_cache_min_uses number Default: 1 Context: http
server
location Reference: proxy_cache_min_uses
Number of queries, after which reply will be cached.proxy_cache_path Syntax: proxy_cache_path path [ levels = levels ] keys_zone = name : size [ inactive = time ] [ max_size = size ] [ loader_files = number ] [ loader_sleep = time ] [ loader_threshold = time ] Default:   Context: http Reference: proxy_cache_path
This directive sets the cache path and other cache parameters. Cached data is stored in files. An MD5 hash of the proxied URL is used as the key for the cache entry, and is also used as the filename in the cache path for the response contents and metadata. The levels parameter sets the number of subdirectory levels in cache. For example:

proxy_cache_path  /data/nginx/cache/one  levels<span>=</span><span>1</span>:<span>2</span>   keys_zone<span>=</span>one:10m<span>;</span>

In this cache, file names will be like the following:

<span>/</span>data<span>/</span>nginx<span>/</span>cache<span>/</span>c<span>/</span><span>29</span><span>/</span>b7f54b2df7773722d382f4809d65029c

You may use any combination of 1 and 2 in the level formats: X, X:X, or X:X:X e.g.: "2", "2:2", "1:1:2". There can be at most 3 levels.All active keys and metadata is stored in shared memory. Zone name and the size of the zone is defined via the keys_zone parameter.Note that each defined zone must have a unique path. For example:

proxy_cache_path  /data/nginx/cache/one    levels<span>=</span><span>1</span>      keys_zone<span>=</span>one:10m<span>;</span>
proxy_cache_path  /data/nginx/cache/two    levels<span>=</span><span>2</span>:<span>2</span>    keys_zone<span>=</span>two:100m<span>;</span>
proxy_cache_path  /data/nginx/cache/three  levels<span>=</span><span>1</span>:<span>1</span>:<span>2</span>  keys_zone<span>=</span>three:1000m<span>;</span>

If cached data is not requested for time defined by the inactive parameter, than that data is removed from the cache. The inactive parameter defaults to 10 minutes (10m).A special process, called "cache manager", is created to control the on-disk cache. It is responsible for removing inactive items and enforcing the size of the cache, as defined by the parameter max_size. When the total size of the cache exceeds the maximum size set by max_size, the least recently used data in the cache is deleted to make room for a new cache entry (a LRU replacement policy).Zone size should be set proportional to number of pages to cache. The size of the metadata for one page (file) depends on the OS; currently it is 64 bytes for FreeBSD/i386, and 128 bytes for FreeBSD/amd64.The directories specified by proxy_cache_path and proxy_temp_path should be located on the same filesystem.proxy_cache_use_stale Syntax: proxy_cache_use_stale error | timeout | invalid_header | updating | http_500 | http_502 | http_503 | http_504 | http_404 | off ... Default: off Context: http
server
location Reference: proxy_cache_use_stale
This directive tells Nginx when to serve a stale item from the proxy cache. The parameters for this directive are similar to proxy_next_upstream with the addition of 'updating'.To prevent cache stampedes (when multiple threads stampede in to try to update the cache simultaneously) you can specify the 'updating' parameter. This will cause one thread to update the cache and while the update is in progress all other threads will serve the stale version of what is in the cache.proxy_cache_valid Syntax: proxy_cache_valid [ code ...] time Default:   Context: http
server
location Reference: proxy_cache_valid
This directive sets the time for caching different replies. Example:

proxy_cache_valid  <span>200</span><span>302</span>  10m<span>;</span>
proxy_cache_valid  <span>404</span>      1m<span>;</span>

sets 10 minutes cache time for replies with code 200 and 302, and 1 minute for 404s.If only time is specified:

proxy_cache_valid 5m<span>;</span>

then only replies with codes 200, 301 and 302 will be cached.Also it is possible to cache any replies with parameter "any":

proxy_cache_valid  <span>200</span><span>302</span> 10m<span>;</span>
proxy_cache_valid  <span>301</span> 1h<span>;</span>
proxy_cache_valid  any 1m<span>;</span>

Upstream cache-related directives have priority over proxy_cache_valid value, in particular the order is (from Igor):

X-Accel-Expires

Expires/Cache-Control

proxy_cache_valid

The order in which your backend return HTTP headers change cache behaviour. Read this post for details.You may ignore the headers using

proxy_ignore_headers X-Accel-Expires Expires Cache-Control<span>;</span>

Concerning If-Modified / Last-Modified since behaviour, please remember that by default nginx sends 304 only if L-M == I-M-S. Controlled by directive if_modified_since [off|exact|before]Note: you must set this option for any persistent caching to occur.proxy_connect_timeout Syntax: proxy_connect_timeout time Default: 60s Context: http
server
location Reference: proxy_connect_timeout
This directive assigns a timeout for the connection to the upstream server. It is necessary to keep in mind that this time out cannot be more than 75 seconds.This is not the time until the server returns the pages, that is the proxy_read_timeout statement. If your upstream server is up, but hanging (e.g. it does not have enough threads to process your request so it puts you in the pool of connections to deal with later), then this statement will not help as the connection to the server has been made.proxy_cookie_domain Syntax: proxy_cookie_domain off 
proxy_cookie_domain domain replacement Default: off Context: http
server
location Appeared in: 1.1.15 Reference: proxy_cookie_domain
proxy_cookie_path Syntax: proxy_cookie_path off 
proxy_cookie_path path replacement Default: off Context: http
server
location Appeared in: 1.1.15 Reference: proxy_cookie_path
proxy_headers_hash_bucket_sizesyntax: proxy_headers_hash_bucket_size size;default: proxy_headers_hash_bucket_size 64;context: http, server, location, ifThis directive sets the bucket size of the headers hash table. 
This determines the limit of the header name. If you use header names longer than 64 characters then increase this.proxy_headers_hash_max_sizesyntax: proxy_headers_hash_max_size size;default: proxy_headers_hash_max_size 512;context: http, server, location, ifThis directive sets the maximum size of the headers hash table. 
Should not be smaller than the amount of headers your back-end is setting.proxy_hide_header Syntax: proxy_hide_header field Default:   Context: http
server
location Reference: proxy_hide_header
nginx does not transfer the "Date", "Server", "X-Pad" and "X-Accel-..." header lines from the proxied server response. The proxy_hide_header directive allows to hide some additional header lines. But if on the contrary the header lines must be passed, then the proxy_pass_header should be used. For example if you want to hide the MS-OfficeWebserver and the AspNet-Version:

<span>location</span> / <span>{</span>
  proxy_hide_header X-AspNet-Version<span>;</span>
  proxy_hide_header MicrosoftOfficeWebServer<span>;</span><span>}</span>

This directive can also be very helpful when using X-Accel-Redirect. For example, you may have one set of backend servers which return the headers for a file download, which includes X-Accel-Redirect to the actual file, as well as the correct Content-Type. However, the Redirect URL points to a files erver which hosts the actual file you wish to serve, and that server sends its own Content-Type header, which might be incorrect, and overrides the header sent by the original backend servers. You can avoid this by adding the proxy_hide_header directive to the fileserver. Example:

<span>location</span> / <span>{</span>
  proxy_pass <span>http</span>://backend_servers<span>;</span><span>}</span>
 
<span>location</span> /files/ <span>{</span>
  proxy_pass <span>http</span>://fileserver<span>;</span>
  proxy_hide_header Content-Type<span>;</span><span>}</span>

proxy_http_version Syntax: proxy_http_version 1.0 | 1.1 Default: 1.0 Context: http
server
location Appeared in: 1.1.4 Reference: proxy_http_version
proxy_ignore_client_abort Syntax: proxy_ignore_client_abort on | off Default: off Context: http
server
location Reference: proxy_ignore_client_abort
Prevents aborting request to proxy in case the client itself aborts the request.proxy_ignore_headers Syntax: proxy_ignore_headers field ... Default:   Context: http
server
location Reference: proxy_ignore_headers
Prohibits the processing of the header lines from the proxy server's response.It can specify the string as "X-Accel-Redirect", "X-Accel-Expires", "Expires", "Cache-Control" or "Set-Cookie". By default, nginx does not caches requests with Set-Cookie.proxy_intercept_errors Syntax: proxy_intercept_errors on | off Default: off Context: http
server
location Reference: proxy_intercept_errors
This directive decides if nginx will intercept responses with HTTP status codes of 400 and higher.By default all responses will be sent as-is from the proxied server.If you set this to on then nginx will intercept status codes that are explicitly handled by an error_page directive. Responses with status codes that do not match an error_page directive will be sent as-is from the proxied server.proxy_max_temp_file_size Syntax: proxy_max_temp_file_size size Default: 1024m Context: http
server
location Reference: proxy_max_temp_file_size
The maximum size of a temporary file when the content is larger than the proxy buffer. If file is larger than this size, it will be served synchronously from upstream server rather than buffered to disk.If proxy_max_temp_file_size is equal to zero, temporary files usage will be disabled.proxy_methodsyntax: proxy_method [method];default: Nonecontext: http, server, locationAllows you to override the HTTP method of the request to be passed to the backend server. If you specify POST for example, all requests forwarded to the backend server will be POST requests.Example:

proxy_method POST<span>;</span>

proxy_next_upstream Syntax: proxy_next_upstream error | timeout | invalid_header | http_500 | http_502 | http_503 | http_504 | http_404 | off ... Default: error timeout Context: http
server
location Reference: proxy_next_upstream
Directive determines in what cases the request will be transmitted to the next server:

error — an error has occurred while connecting to the server, sending a request to it, or reading its response;

timeout — occurred timeout during the connection with the server, transfer the request or while reading response from the server;

invalid_header — server returned a empty or incorrect answer;

http_500 — server returned answer with code 500

http_502 — server returned answer with code 502

http_503 — server returned answer with code 503

http_504 — server returned answer with code 504

http_404 — server returned answer with code 404

off — it forbids the request transfer to the next server

Transferring the request to the next server is only possible when nothing has been transferred to the client -- that is, if an error or timeout arises in the middle of the transfer of the request, then it is not possible to retry the current request on a different server.proxy_no_cache Syntax: proxy_no_cache string ... Default:   Context: http
server
location Reference: proxy_no_cache
Specifies in what cases a response will not be cached, e.g.

proxy_no_cache <span>$cookie_nocache</span><span>$arg_nocache</span><span>$arg_comment</span><span>;</span>
proxy_no_cache <span>$http_pragma</span><span>$http_authorization</span><span>;</span>

The response is marked uncacheable if any of the arguments expand to anything other than "0" or the empty string. For instance, in the above example, the response will never be cached if the cookie "nocache" is set in the request.proxy_pass Syntax: proxy_pass URL Default:   Context: location
if in location
limit_except Reference: proxy_pass
This directive sets the address of the proxied server and the URI to which location will be mapped. Address may be given as hostname or address and port, for example,

proxy_pass <span>http</span>://localhost:<span>8000</span>/uri/<span>;</span>

or as unix socket path:

proxy_pass <span>http</span>://unix:/path/to/backend.socket:/uri/<span>;</span>

path is given after the word unix between two colons.By default, the Host header from the request is not forwarded, but is set based on the proxy_pass statement. To forward the requested Host header, it is necessary to use:

proxy_set_header Host <span>$host</span><span>;</span>

While passing request nginx replaces URI part which corresponds to location with one indicated in proxy_pass direct