Traefik requires access to the docker socket to get its dynamic configuration,
by watching the Docker API through this socket.
!!! important
Depending on your context and your usage, accessing the Docker API without any restriction might be a security concern.
As explained on the Docker documentation: ([Docker Daemon Attack Surface page](https://docs.docker.com/engine/security/security/#docker-daemon-attack-surface)):
`[...] only **trusted** users should be allowed to control your Docker daemon [...]`
If the Traefik processes (handling requests from the outside world) is attacked,
then the attacker can access the Docker (or Swarm Mode) backend.
Also, when using Swarm Mode, it is mandatory to schedule Traefik's containers on the Swarm manager nodes,
to let Traefik accessing the Docker Socket of the Swarm manager node.
More information about Docker's security:
- [KubeCon EU 2018 Keynote, Running with Scissors, from Liz Rice](https://www.youtube.com/watch?v=ltrV-Qmh3oY)
- [Don't expose the Docker socket (not even to a container)](https://www.lvh.io/posts/dont-expose-the-docker-socket-not-even-to-a-container.html)
- [A thread on Stack Overflow about sharing the `/var/run/docker.sock` file](https://news.ycombinator.com/item?id=17983623)
- [To Dind or not to DinD](https://blog.loof.fr/2018/01/to-dind-or-not-do-dind.html)
### Security Compensation
The main security compensation is to expose the Docker socket over TCP, instead of the default Unix socket file.
It allows different implementation levels of the [AAA (Authentication, Authorization, Accounting) concepts](https://en.wikipedia.org/wiki/AAA_(computer_security)), depending on your security assessment:
- Authentication with Client Certificates as described in [the "Protect the Docker daemon socket" page of Docker's documentation](https://docs.docker.com/engine/security/https/)
- Authorization with the [Docker Authorization Plugin Mechanism](https://docs.docker.com/engine/extend/plugins_authorization/)
- Accounting at networking level, by exposing the socket only inside a Docker private network, only available for Traefik.
- Accounting at container level, by exposing the socket on a another container than Traefik's.
With Swarm mode, it allows scheduling of Traefik on worker nodes, with only the "socket exposer" container on the manager nodes.
- Accounting at kernel level, by enforcing kernel calls with mechanisms like [SELinux](https://en.wikipedia.org/wiki/Security-Enhanced_Linux),
to only allows an identified set of actions for Traefik's process (or the "socket exposer" process).
Use the following ressources to get started:
- [Traefik issue GH-4174 about security with Docker socket](https://github.com/containous/traefik/issues/4174)
- [Inspecting Docker Activity with Socat](https://developers.redhat.com/blog/2015/02/25/inspecting-docker-activity-with-socat/)
- [Letting Traefik run on Worker Nodes](https://blog.mikesir87.io/2018/07/letting-traefik-run-on-worker-nodes/)
- [Docker Socket Proxy from Tecnativa](https://github.com/Tecnativa/docker-socket-proxy)
If you are intending to use only Docker Compose commands (e.g. `docker-compose up --scale whoami=2 -d`), labels should be under your service, otherwise they will be ignored.
| `traefik.docker.network` | Overrides the default docker network to use for connections to the container. [1] |
| `traefik.domain` | Sets the default base domain for the frontend rules. For more information, check the [Container Labels section's of the user guide "Let's Encrypt & Docker"](/user-guide/docker-and-lets-encrypt/#container-labels) |
| `traefik.backend.responseForwarding.flushInterval=10ms` | Defines the interval between two flushes when forwarding response from backend to client. |
| `traefik.backend.maxconn.amount=10` | Sets a maximum number of connections to the backend.<br>Must be used in conjunction with the below label to take effect. |
| `traefik.backend.maxconn.extractorfunc=client.ip` | Sets the function to be used against the request to determine what to limit maximum connections to the backend by.<br>Must be used in conjunction with the above label to take effect. |
| `traefik.frontend.auth.basic=EXPR` | Sets the basic authentication to this frontend in CSV format: `User:Hash,User:Hash` [2] (DEPRECATED). |
| `traefik.frontend.auth.basic.removeHeader=true` | If set to `true`, removes the `Authorization` header. |
| `traefik.frontend.auth.basic.users=EXPR` | Sets the basic authentication to this frontend in CSV format: `User:Hash,User:Hash` [2]. |
| `traefik.frontend.auth.basic.usersFile=/path/.htpasswd` | Sets the basic authentication with an external file; if users and usersFile are provided, both are merged, with external file contents having precedence. |
| `traefik.frontend.auth.digest.removeHeader=true` | If set to `true`, removes the `Authorization` header. |
| `traefik.frontend.auth.digest.users=EXPR` | Sets the digest authentication to this frontend in CSV format: `User:Realm:Hash,User:Realm:Hash`. |
| `traefik.frontend.auth.digest.usersFile=/path/.htdigest` | Sets the digest authentication with an external file; if users and usersFile are provided, both are merged, with external file contents having precedence. |
| `traefik.frontend.auth.forward.address=https://example.com` | Sets the URL of the authentication server. |
| `traefik.frontend.auth.forward.tls.ca=/path/ca.pem` | Sets the Certificate Authority (CA) for the TLS connection with the authentication server. |
| `traefik.frontend.auth.forward.tls.caOptional=true` | Checks the certificates if present but do not force to be signed by a specified Certificate Authority (CA). |
| `traefik.frontend.auth.forward.tls.cert=/path/server.pem` | Sets the Certificate for the TLS connection with the authentication server. |
| `traefik.frontend.auth.forward.tls.insecureSkipVerify=true` | If set to true invalid SSL certificates are accepted. |
| `traefik.frontend.auth.forward.tls.key=/path/server.key` | Sets the Certificate for the TLS connection with the authentication server. |
| `traefik.frontend.auth.headerField=X-WebAuth-User` | Sets the header user to pass the authenticated user to the application. |
| `traefik.frontend.entryPoints=http,https` | Assigns this frontend to entry points `http` and `https`.<br>Overrides `defaultEntryPoints` |
| `traefik.frontend.errors.<name>.backend=NAME` | See [custom error pages](/configuration/commons/#custom-error-pages) section. |
| `traefik.frontend.errors.<name>.query=PATH` | See [custom error pages](/configuration/commons/#custom-error-pages) section. |
| `traefik.frontend.errors.<name>.status=RANGE` | See [custom error pages](/configuration/commons/#custom-error-pages) section. |
| `traefik.frontend.passHostHeader=true` | Forwards client `Host` header to the backend. |
| `traefik.frontend.passTLSClientCert.infos.notAfter=true` | Add the noAfter field in a escaped client infos in the `X-Forwarded-Ssl-Client-Cert-Infos` header. |
| `traefik.frontend.passTLSClientCert.infos.notBefore=true` | Add the noBefore field in a escaped client infos in the `X-Forwarded-Ssl-Client-Cert-Infos` header. |
| `traefik.frontend.passTLSClientCert.infos.sans=true` | Add the sans field in a escaped client infos in the `X-Forwarded-Ssl-Client-Cert-Infos` header. |
| `traefik.frontend.passTLSClientCert.infos.subject.commonName=true` | Add the subject.commonName field in a escaped client infos in the `X-Forwarded-Ssl-Client-Cert-Infos` header. |
| `traefik.frontend.passTLSClientCert.infos.subject.country=true` | Add the subject.country field in a escaped client infos in the `X-Forwarded-Ssl-Client-Cert-Infos` header. |
| `traefik.frontend.passTLSClientCert.infos.subject.locality=true` | Add the subject.locality field in a escaped client infos in the `X-Forwarded-Ssl-Client-Cert-Infos` header. |
| `traefik.frontend.passTLSClientCert.infos.subject.organization=true`| Add the subject.organization field in a escaped client infos in the `X-Forwarded-Ssl-Client-Cert-Infos` header. |
| `traefik.frontend.passTLSClientCert.infos.subject.province=true` | Add the subject.province field in a escaped client infos in the `X-Forwarded-Ssl-Client-Cert-Infos` header. |
| `traefik.frontend.passTLSClientCert.infos.subject.serialNumber=true`| Add the subject.serialNumber field in a escaped client infos in the `X-Forwarded-Ssl-Client-Cert-Infos` header. |
| `traefik.frontend.passTLSClientCert.pem=true` | Pass the escaped pem in the `X-Forwarded-Ssl-Client-Cert` header. |
| `traefik.frontend.passTLSCert=true` | Forwards TLS Client certificates to the backend (DEPRECATED). |
| `traefik.frontend.rateLimit.extractorFunc=EXP` | See [rate limiting](/configuration/commons/#rate-limiting) section. |
| `traefik.frontend.rateLimit.rateSet.<name>.period=6` | See [rate limiting](/configuration/commons/#rate-limiting) section. |
| `traefik.frontend.rateLimit.rateSet.<name>.average=6` | See [rate limiting](/configuration/commons/#rate-limiting) section. |
| `traefik.frontend.rateLimit.rateSet.<name>.burst=6` | See [rate limiting](/configuration/commons/#rate-limiting) section. |
| `traefik.frontend.redirect.entryPoint=https` | Enables Redirect to another entryPoint to this frontend (e.g. HTTPS) |
| `traefik.frontend.redirect.regex=^http://localhost/(.*)` | Redirects to another URL to this frontend.<br>Must be set with `traefik.frontend.redirect.replacement`. |
| `traefik.frontend.redirect.replacement=http://mydomain/$1` | Redirects to another URL to this frontend.<br>Must be set with `traefik.frontend.redirect.regex`. |
| `traefik.frontend.redirect.permanent=true` | Returns 301 instead of 302. |
| `traefik.frontend.rule=EXPR` | Overrides the default frontend rule. Default: `Host:{containerName}.{domain}` or `Host:{service}.{project_name}.{domain}` if you are using `docker-compose`. |
| `traefik.frontend.whiteList.sourceRange=RANGE` | Sets a list of IP-Ranges which are allowed to access.<br>An unset or empty list allows all Source-IPs to access.<br>If one of the Net-Specifications are invalid, the whole list is invalid and allows all Source-IPs to access. |
| `traefik.frontend.whiteList.ipStrategy=true` | Uses the default IPStrategy.<br>Can be used when there is an existing `clientIPStrategy` but you want the remote address for whitelisting. |
| `traefik.frontend.whiteList.ipStrategy.depth=5` | See [whitelist](/configuration/entrypoints/#white-listing) |
| `traefik.frontend.whiteList.ipStrategy.excludedIPs=127.0.0.1` | See [whitelist](/configuration/entrypoints/#white-listing) |
If a container is linked to several networks, be sure to set the proper network name (you can check with `docker inspect <container_id>`) otherwise it will randomly pick one (depending on how docker is returning them).
| `traefik.frontend.headers.customRequestHeaders=EXPR` | Provides the container with custom request headers that will be appended to each request forwarded to the container.<br>Format: <code>HEADER:value||HEADER2:value2</code> |
| `traefik.frontend.headers.customResponseHeaders=EXPR` | Appends the headers to each response returned by the container, before forwarding the response to the client.<br>Format: <code>HEADER:value||HEADER2:value2</code> |
| `traefik.frontend.headers.hostsProxyHeaders=EXPR` | Provides a list of headers that the proxied hostname may be stored.<br>Format: `HEADER1,HEADER2` |
| `traefik.frontend.headers.isDevelopment=false` | This will cause the `AllowedHosts`, `SSLRedirect`, and `STSSeconds`/`STSIncludeSubdomains` options to be ignored during development.<br>When deploying to production, be sure to set this to false. |
| `traefik.frontend.headers.SSLRedirect=true` | Forces the frontend to redirect to SSL if a non-SSL request is sent. |
| `traefik.frontend.headers.SSLTemporaryRedirect=true` | Forces the frontend to redirect to SSL if a non-SSL request is sent, but by sending a 302 instead of a 301. |
| `traefik.frontend.headers.SSLHost=HOST` | This setting configures the hostname that redirects will be based on. Default is "", which is the same host as the request. |
| `traefik.frontend.headers.SSLForceHost=true` | If `SSLForceHost` is `true` and `SSLHost` is set, requests will be forced to use `SSLHost` even the ones that are already using SSL. Default is false. |
| `traefik.frontend.headers.SSLProxyHeaders=EXPR` | Header combinations that would signify a proper SSL Request (Such as `X-Forwarded-For:https`).<br>Format: <code>HEADER:value||HEADER2:value2</code> |
| `traefik.<segment_name>.frontend.auth.forward.tls.ca=/path/ca.pem` | Same as `traefik.frontend.auth.forward.tls.ca` |
| `traefik.<segment_name>.frontend.auth.forward.tls.caOptional=true` | Same as `traefik.frontend.auth.forward.tls.caOptional` |
| `traefik.<segment_name>.frontend.auth.forward.tls.cert=/path/server.pem` | Same as `traefik.frontend.auth.forward.tls.cert` |
| `traefik.<segment_name>.frontend.auth.forward.tls.insecureSkipVerify=true` | Same as `traefik.frontend.auth.forward.tls.insecureSkipVerify` |
| `traefik.<segment_name>.frontend.auth.forward.tls.key=/path/server.key` | Same as `traefik.frontend.auth.forward.tls.key` |
| `traefik.<segment_name>.frontend.auth.forward.trustForwardHeader=true` | Same as `traefik.frontend.auth.forward.trustForwardHeader` |
| `traefik.<segment_name>.frontend.auth.headerField=X-WebAuth-User` | Same as `traefik.frontend.auth.headerField` |
| `traefik.<segment_name>.frontend.entryPoints=https` | Same as `traefik.frontend.entryPoints` |
| `traefik.<segment_name>.frontend.errors.<name>.backend=NAME` | Same as `traefik.frontend.errors.<name>.backend` |
| `traefik.<segment_name>.frontend.errors.<name>.query=PATH` | Same as `traefik.frontend.errors.<name>.query` |
| `traefik.<segment_name>.frontend.errors.<name>.status=RANGE` | Same as `traefik.frontend.errors.<name>.status` |
| `traefik.<segment_name>.frontend.passHostHeader=true` | Same as `traefik.frontend.passHostHeader` |
| `traefik.<segment_name>.frontend.passTLSClientCert.infos.notAfter=true` | Same as `traefik.frontend.passTLSClientCert.infos.notAfter` |
| `traefik.<segment_name>.frontend.passTLSClientCert.infos.notBefore=true` | Same as `traefik.frontend.passTLSClientCert.infos.notBefore` |
| `traefik.<segment_name>.frontend.passTLSClientCert.infos.sans=true` | Same as `traefik.frontend.passTLSClientCert.infos.sans` |
| `traefik.<segment_name>.frontend.passTLSClientCert.infos.subject.commonName=true` | Same as `traefik.frontend.passTLSClientCert.infos.subject.commonName` |
| `traefik.<segment_name>.frontend.passTLSClientCert.infos.subject.country=true` | Same as `traefik.frontend.passTLSClientCert.infos.subject.country` |
| `traefik.<segment_name>.frontend.passTLSClientCert.infos.subject.locality=true` | Same as `traefik.frontend.passTLSClientCert.infos.subject.locality` |
| `traefik.<segment_name>.frontend.passTLSClientCert.infos.subject.organization=true`| Same as `traefik.frontend.passTLSClientCert.infos.subject.organization`|
| `traefik.<segment_name>.frontend.passTLSClientCert.infos.subject.province=true` | Same as `traefik.frontend.passTLSClientCert.infos.subject.province` |
| `traefik.<segment_name>.frontend.passTLSClientCert.infos.subject.serialNumber=true`| Same as `traefik.frontend.passTLSClientCert.infos.subject.serialNumber`|
| `traefik.<segment_name>.frontend.passTLSClientCert.pem=true` | Same as `traefik.frontend.passTLSClientCert.infos.pem` |
| `traefik.<segment_name>.frontend.passTLSCert=true` | Same as `traefik.frontend.passTLSCert` |
| `traefik.<segment_name>.frontend.priority=10` | Same as `traefik.frontend.priority` |
| `traefik.<segment_name>.frontend.rateLimit.extractorFunc=EXP` | Same as `traefik.frontend.rateLimit.extractorFunc` |
| `traefik.<segment_name>.frontend.rateLimit.rateSet.<name>.period=6` | Same as `traefik.frontend.rateLimit.rateSet.<name>.period` |
| `traefik.<segment_name>.frontend.rateLimit.rateSet.<name>.average=6` | Same as `traefik.frontend.rateLimit.rateSet.<name>.average` |
| `traefik.<segment_name>.frontend.rateLimit.rateSet.<name>.burst=6` | Same as `traefik.frontend.rateLimit.rateSet.<name>.burst` |
| `traefik.<segment_name>.frontend.redirect.entryPoint=https` | Same as `traefik.frontend.redirect.entryPoint` |
| `traefik.<segment_name>.frontend.redirect.regex=^http://localhost/(.*)` | Same as `traefik.frontend.redirect.regex` |
| `traefik.<segment_name>.frontend.redirect.replacement=http://mydomain/$1` | Same as `traefik.frontend.redirect.replacement` |
| `traefik.<segment_name>.frontend.redirect.permanent=true` | Same as `traefik.frontend.redirect.permanent` |
| `traefik.<segment_name>.frontend.rule=EXP` | Same as `traefik.frontend.rule` |
| `traefik.<segment_name>.frontend.whiteList.sourceRange=RANGE` | Same as `traefik.frontend.whiteList.sourceRange` |
If a label is defined both as a `container label` and a `segment label` (for example `traefik.<segment_name>.port=PORT` and `traefik.port=PORT` ), the `segment label` is used to defined the `<segment_name>` property (`port` in the example).
It's possible to mix `container labels` and `segment labels`, in this case `container labels` are used as default value for missing `segment labels` but no frontends are going to be created with the `container labels`.
When used in conjunction with the `traefik.port` label (that tells Traefik to route requests to a specific port), Traefik tries to find a binding with `traefik.port` port to select the container. If it can't find such a binding, Traefik falls back on the internal network IP of the container, but still uses the `traefik.port` that is set in the label.
In the above table, ExtIp stands for "external IP found in the binding", IntIp stands for "internal network container's IP", ExtPort stands for "external Port found in the binding", and IntPort stands for "internal network container's port."
