traefik/docs/content/middlewares/http/headers.md

title	description
Traefik Headers Documentation	In Traefik Proxy, the HTTP headers middleware manages the headers of requests and responses. Read the technical documentation.

Headers

Managing Request/Response headers {: .subtitle }

The Headers middleware manages the headers of requests and responses.

A set of forwarded headers are automatically added by default. See the FAQ for more information.

Configuration Examples

Adding Headers to the Request and the Response

The following example adds the X-Script-Name header to the proxied request and the X-Custom-Response-Header header to the response

labels:
  - "traefik.http.middlewares.testHeader.headers.customrequestheaders.X-Script-Name=test"
  - "traefik.http.middlewares.testHeader.headers.customresponseheaders.X-Custom-Response-Header=value"

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: test-header
spec:
  headers:
    customRequestHeaders:
      X-Script-Name: "test"
    customResponseHeaders:
      X-Custom-Response-Header: "value"

- "traefik.http.middlewares.testheader.headers.customrequestheaders.X-Script-Name=test"
- "traefik.http.middlewares.testheader.headers.customresponseheaders.X-Custom-Response-Header=value"

http:
  middlewares:
    testHeader:
      headers:
        customRequestHeaders:
          X-Script-Name: "test"
        customResponseHeaders:
          X-Custom-Response-Header: "value"

[http.middlewares]
  [http.middlewares.testHeader.headers]
    [http.middlewares.testHeader.headers.customRequestHeaders]
        X-Script-Name = "test"
    [http.middlewares.testHeader.headers.customResponseHeaders]
        X-Custom-Response-Header = "value"

Adding and Removing Headers

In the following example, requests are proxied with an extra X-Script-Name header while their X-Custom-Request-Header header gets stripped, and responses are stripped of their X-Custom-Response-Header header.

labels:
  - "traefik.http.middlewares.testheader.headers.customrequestheaders.X-Script-Name=test"
  - "traefik.http.middlewares.testheader.headers.customrequestheaders.X-Custom-Request-Header="
  - "traefik.http.middlewares.testheader.headers.customresponseheaders.X-Custom-Response-Header="

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: test-header
spec:
  headers:
    customRequestHeaders:
      X-Script-Name: "test" # Adds
      X-Custom-Request-Header: "" # Removes
    customResponseHeaders:
      X-Custom-Response-Header: "" # Removes

- "traefik.http.middlewares.testheader.headers.customrequestheaders.X-Script-Name=test"
- "traefik.http.middlewares.testheader.headers.customrequestheaders.X-Custom-Request-Header="
- "traefik.http.middlewares.testheader.headers.customresponseheaders.X-Custom-Response-Header="

http:
  middlewares:
    testHeader:
      headers:
        customRequestHeaders:
          X-Script-Name: "test" # Adds
          X-Custom-Request-Header: "" # Removes
        customResponseHeaders:
          X-Custom-Response-Header: "" # Removes

[http.middlewares]
  [http.middlewares.testHeader.headers]
    [http.middlewares.testHeader.headers.customRequestHeaders]
        X-Script-Name = "test" # Adds
        X-Custom-Request-Header = "" # Removes
    [http.middlewares.testHeader.headers.customResponseHeaders]
        X-Custom-Response-Header = "" # Removes

Using Security Headers

Security-related headers (HSTS headers, Browser XSS filter, etc) can be managed similarly to custom headers as shown above. This functionality makes it possible to easily use security features by adding headers.

labels:
  - "traefik.http.middlewares.testHeader.headers.framedeny=true"
  - "traefik.http.middlewares.testHeader.headers.browserxssfilter=true"

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: test-header
spec:
  headers:
    frameDeny: true
    browserXssFilter: true

- "traefik.http.middlewares.testheader.headers.framedeny=true"
- "traefik.http.middlewares.testheader.headers.browserxssfilter=true"

http:
  middlewares:
    testHeader:
      headers:
        frameDeny: true
        browserXssFilter: true

[http.middlewares]
  [http.middlewares.testHeader.headers]
    frameDeny = true
    browserXssFilter = true

CORS Headers

CORS (Cross-Origin Resource Sharing) headers can be added and configured in a manner similar to the custom headers above. This functionality allows for more advanced security features to quickly be set. If CORS headers are set, then the middleware does not pass preflight requests to any service, instead the response will be generated and sent back to the client directly.
Please note that the example below is by no means authoritative or exhaustive, and should not be used as is for production.

labels:
  - "traefik.http.middlewares.testheader.headers.accesscontrolallowmethods=GET,OPTIONS,PUT"
  - "traefik.http.middlewares.testheader.headers.accesscontrolallowheaders=*"
  - "traefik.http.middlewares.testheader.headers.accesscontrolalloworiginlist=https://foo.bar.org,https://example.org"
  - "traefik.http.middlewares.testheader.headers.accesscontrolmaxage=100"
  - "traefik.http.middlewares.testheader.headers.addvaryheader=true"

apiVersion: traefik.io/v1alpha1
kind: Middleware
metadata:
  name: test-header
spec:
  headers:
    accessControlAllowMethods:
      - "GET"
      - "OPTIONS"
      - "PUT"
    accessControlAllowHeaders:
      - "*"
    accessControlAllowOriginList:
      - "https://foo.bar.org"
      - "https://example.org"
    accessControlMaxAge: 100
    addVaryHeader: true

- "traefik.http.middlewares.testheader.headers.accesscontrolallowmethods=GET,OPTIONS,PUT"
- "traefik.http.middlewares.testheader.headers.accesscontrolallowheaders=*"
- "traefik.http.middlewares.testheader.headers.accesscontrolalloworiginlist=https://foo.bar.org,https://example.org"
- "traefik.http.middlewares.testheader.headers.accesscontrolmaxage=100"
- "traefik.http.middlewares.testheader.headers.addvaryheader=true"

http:
  middlewares:
    testHeader:
      headers:
        accessControlAllowMethods:
          - GET
          - OPTIONS
          - PUT
        accessControlAllowHeaders: "*"
        accessControlAllowOriginList:
          - https://foo.bar.org
          - https://example.org
        accessControlMaxAge: 100
        addVaryHeader: true

[http.middlewares]
  [http.middlewares.testHeader.headers]
    accessControlAllowMethods = ["GET", "OPTIONS", "PUT"]
    accessControlAllowHeaders = [ "*" ]
    accessControlAllowOriginList = ["https://foo.bar.org","https://example.org"]
    accessControlMaxAge = 100
    addVaryHeader = true

Configuration Options

General

!!! warning

Custom headers will overwrite existing headers if they have identical names.

!!! note ""

The detailed documentation for security headers can be found in [unrolled/secure](https://github.com/unrolled/secure#available-options).

customRequestHeaders

The customRequestHeaders option lists the header names and values to apply to the request.

customResponseHeaders

The customResponseHeaders option lists the header names and values to apply to the response.

accessControlAllowCredentials

The accessControlAllowCredentials indicates whether the request can include user credentials.

accessControlAllowHeaders

The accessControlAllowHeaders indicates which header field names can be used as part of the request.

accessControlAllowMethods

The accessControlAllowMethods indicates which methods can be used during requests.

accessControlAllowOriginList

The accessControlAllowOriginList indicates whether a resource can be shared by returning different values.

A wildcard origin * can also be configured, and matches all requests. If this value is set by a backend service, it will be overwritten by Traefik.

This value can contain a list of allowed origins.

More information including how to use the settings can be found at:

• Mozilla.org
• w3
• IETF

Traefik no longer supports the null value, as it is no longer recommended as a return value.

accessControlAllowOriginListRegex

The accessControlAllowOriginListRegex option is the counterpart of the accessControlAllowOriginList option with regular expressions instead of origin values. It allows all origins that contain any match of a regular expression in the accessControlAllowOriginList.

!!! tip

Regular expressions and replacements can be tested using online tools such as [Go Playground](https://play.golang.org/p/mWU9p-wk2ru) or the [Regex101](https://regex101.com/r/58sIgx/2).

When defining a regular expression within YAML, any escaped character needs to be escaped twice: `example\.com` needs to be written as `example\\.com`.

accessControlExposeHeaders

The accessControlExposeHeaders indicates which headers are safe to expose to the api of a CORS API specification.

accessControlMaxAge

The accessControlMaxAge indicates how many seconds a preflight request can be cached for.

addVaryHeader

The addVaryHeader is used in conjunction with accessControlAllowOriginList to determine whether the Vary header should be added or modified to demonstrate that server responses can differ based on the value of the origin header.

allowedHosts

The allowedHosts option lists fully qualified domain names that are allowed.

hostsProxyHeaders

The hostsProxyHeaders option is a set of header keys that may hold a proxied hostname value for the request.

sslProxyHeaders

The sslProxyHeaders option is set of header keys with associated values that would indicate a valid HTTPS request. It can be useful when using other proxies (example: "X-Forwarded-Proto": "https").

stsSeconds

The stsSeconds is the max-age of the Strict-Transport-Security header. If set to 0, the header is not set.

stsIncludeSubdomains

If the stsIncludeSubdomains is set to true, the includeSubDomains directive is appended to the Strict-Transport-Security header.

stsPreload

Set stsPreload to true to have the preload flag appended to the Strict-Transport-Security header.

forceSTSHeader

Set forceSTSHeader to true to add the STS header even when the connection is HTTP.

frameDeny

Set frameDeny to true to add the X-Frame-Options header with the value of DENY.

customFrameOptionsValue

The customFrameOptionsValue allows the X-Frame-Options header value to be set with a custom value. This overrides the FrameDeny option.

contentTypeNosniff

Set contentTypeNosniff to true to add the X-Content-Type-Options header with the value nosniff.

browserXssFilter

Set browserXssFilter to true to add the X-XSS-Protection header with the value 1; mode=block.

customBrowserXSSValue

The customBrowserXssValue option allows the X-XSS-Protection header value to be set with a custom value. This overrides the BrowserXssFilter option.

contentSecurityPolicy

The contentSecurityPolicy option allows the Content-Security-Policy header value to be set with a custom value.

publicKey

The publicKey implements HPKP to prevent MITM attacks with forged certificates.

referrerPolicy

The referrerPolicy allows sites to control whether browsers forward the Referer header to other sites.

permissionsPolicy

The permissionsPolicy allows sites to control browser features.

isDevelopment

Set isDevelopment to true when developing to mitigate the unwanted effects of the AllowedHosts, SSL, and STS options. Usually testing takes place using HTTP, not HTTPS, and on localhost, not your production domain. If you would like your development environment to mimic production with complete Host blocking, SSL redirects, and STS headers, leave this as false.

{!traefik-for-business-applications.md!}