Traefik Get Real IP address

When traefik is deployed behind multiple load balancers, this plugin can be used to detect different load balancers and extract the real IP from different header fields, then output the value to the x-real-ip header.

This plugin can prevent IP spoofing by checking if the values form the received header information of the load balancer match before extracting the IP address.

For example, in the configuration of CloudFlare load balancer shown below, we configure it to only accept the header x-from-cdn with a value equal to cf-foo, and extract the IP address from the Cf-Connecting-Ip header. Since users never know about the existence of the x-from-cdn header or its required value cf-foo, it remains secure 🛡️. To increase complexity and avoid being guessed, you can use a random string :)

 CloudFlare
┌─────────┐
│         ├────────────────────────────────►  ┌───────┬────────┐
└─────────┘ x-from-cdn:cf-foo                 │       │        │
            Cf-Connecting-Ip: realip          │       │        │
 CDN2                                         │       │        │
┌─────────┐                                   │       │ paxxs's│
│         ├────────────────────────────────►  │traefik│        │ x-real-ip:realip
└─────────┘ x-from-cdn:mf-bar                 │       │Get-rea ├─────────────►
            Client-iP: realip                 │       │ l-ip   │
 CDN3                                         │       │Plugin  │
┌─────────┐                                   │       │        │
│         ├───────────────────────────────►   │       │        │
└─────────┘ x-from-cdn:mf-fun                 └───────┴────────┘
            x-forwarded-for: realip,x.x.x.x
                           (truthedIP)          ▲  ▲
                                                │  │
 ┌────────┐                                     │  │
 └────────┘ ────────────────────────────────────┘  │
   "*"                                             │
 ┌────────┐                RemoteAddr/etc..        │
 └────────┘ ───────────────────────────────────────┘

CDN Configuration

E.g. Cloudflare:

Rules > Transform Rules > HTTP Request Header Modification > Add

• Set static Header: X-From-Cdn
  • Value: cf-foo

Traefik Configuration

Static

Plugin Info:

• moduleName: github.com/Paxxs/traefik-get-real-ip
• version: v1.0.2

Traefik Configuration:

• yml
• toml
• docker-labels

pilot:
  token: [REDACTED]

experimental:
  plugins:
    real-ip:
      moduleName: github.com/Paxxs/traefik-get-real-ip
      version: [Please fill the latest version !]

Dynamic

• yml
• toml
• docker labels
• Kubernetes

http:
  middlewares:
    real-ip-foo:
      plugin:
        real-ip:
          Proxy:
            - proxyHeadername: X-From-Cdn
              proxyHeadervalue: mf-fun
              realIP: X-Forwarded-For
            - proxyHeadername: X-From-Cdn
              proxyHeadervalue: mf-bar
              realIP: Client-Ip
              OverwriteXFF: true # default: false, v1.0.2 or above
            - proxyHeadername: X-From-Cdn
              proxyHeadervalue: cf-foo
              realIP: Cf-Connecting-Ip
              OverwriteXFF: true # default: false, v1.0.2 or above
            - proxyHeadername: "*"
              realIP: RemoteAddr

  routers:
    my-router:
      rule: Host(`localhost`)
      middlewares:
        - real-ip-foo
      service: my-service

  services:
    my-service:
      loadBalancer:
        servers:
          - url: 'http://127.0.0.1'