IMAPS with Proxy Protocol Example

Summary

The IMAPS with Proxy Protocol example shows how to serve IMAPS on TCP port 993 and IMAP on TCP port 143 sending the PROXY protocol headers to a single IMAP backend on TCP port 1143.

Configuration

Caddyfile

{
    layer4 {
        :993 {
            @imaps tls sni imap.example.com
            route @imaps {
                tls
                proxy {
                    # send proxy protocol v1
                    proxy_protocol v1
                    upstream localhost:143
                }
            }
        }
        :143 {
            route {
                # receive proxy protocol v1 or v2
                proxy_protocol
                proxy {
                    # send proxy protocol v2
                    proxy_protocol v2
                    upstream localhost:1143
                }
            }
        }
    }
}

# automatically obtain SSL certificates
# used for TLS termination on port 993
imap.example.com {
    respond "OK" 200
}

JSON

{
    "apps":{
        "http":{
            "servers":{
                "srv0":{
                    "listen":[
                        ":443"
                    ],
                    "routes":[
                        {
                            "match":[
                                {
                                    "host":[
                                        "imap.example.com"
                                    ]
                                }
                            ],
                            "handle":[
                                {
                                    "handler":"subroute",
                                    "routes":[
                                        {
                                            "handle":[
                                                {
                                                    "body":"OK",
                                                    "handler":"static_response",
                                                    "status_code":200
                                                }
                                            ]
                                        }
                                    ]
                                }
                            ],
                            "terminal":true
                        }
                    ]
                }
            }
        },
        "layer4":{
            "servers":{
                "srv0":{
                    "listen":[
                        ":993"
                    ],
                    "routes":[
                        {
                            "match":[
                                {
                                    "tls":{
                                        "sni":[
                                            "imap.example.com"
                                        ]
                                    }
                                }
                            ],
                            "handle":[
                                {
                                    "handler":"tls"
                                },
                                {
                                    "handler":"proxy",
                                    "proxy_protocol":"v1",
                                    "upstreams":[
                                        {
                                            "dial":[
                                                "localhost:143"
                                            ]
                                        }
                                    ]
                                }
                            ]
                        }
                    ]
                },
                "srv1":{
                    "listen":[
                        ":143"
                    ],
                    "routes":[
                        {
                            "handle":[
                                {
                                    "handler":"proxy_protocol"
                                },
                                {
                                    "handler":"proxy",
                                    "proxy_protocol":"v2",
                                    "upstreams":[
                                        {
                                            "dial":[
                                                "localhost:1143"
                                            ]
                                        }
                                    ]
                                }
                            ]
                        }
                    ]
                }
            }
        }
    }
}