config.schema.json

{
	"$schema": "http://json-schema.org/draft-07/schema#", 
	"title": "Root", 
	"type": "object",
	"required": [
        "mode"
	],
    "oneOf": [
        {
            "properties": {
                "mode": {
                    "const": "full",
                    "description": "Run SMTP server and relay emails to the Graph API"
                }
            },
            "required": ["send"]
        },
        {
            "properties": {
                "mode": {
                    "const": "receive",
                    "description": "Only run SMTP server and place received emails in queue (do not send them)"
                }
            }
        },
        {
            "properties": {
                "mode": {
                    "const": "send",
                    "description": "Only send items from the queue folder, but do not run the SMTP server to accept emails"
                }
            },
            "required": ["send"]
        }
    ],
    "definitions": {
        "emailArray": {
            "type": "array",
            "items": {
                "type": "string",
                "pattern": "^[\\w\\-\\.]+@([\\w-]+\\.)+[\\w-]{2,}$"
            }
        },
        "ipaddress": {
            "type": "string",
            "anyOf": [
                {
                    "description": "IPv4 address",
                    "pattern": "^[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}$"
                },
                {
                    "description": "IPv6 address",
                    "pattern": "^(([a-fA-F0-9]{1,4}:){0,7}|:):?[a-fA-F0-9]{1,4}$"
                }
            ]
        },
        "ipCIDR": {
            "type": "string",
            "anyOf": [
                {
                    "description": "IPv4 CIDR",
                    "pattern": "^[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\/[1-3]?[0-9]$"
                },
                {
                    "description": "IPv6 CIDR",
                    "pattern": "^(([a-fA-F0-9]{1,4}:){0,7}|:):?([a-fA-F0-9]{1,4})?\/1?[0-9]{2}$"
                }
            ]
        }
    },
	"properties": {
        "mode": {
            "title": "Operation mode",
            "type": "string"
        },
        "send": {
            "type": "object",
            "required": [
                "appReg"
            ],
            "properties": {
                "appReg": {
                    "title": "Entra ID application registration",
                    "type": "object",
                    "required": ["tenant","id"],
                    "oneOf": [
                        {"required": ["secret"]},
                        {"required": ["certificate"]}
                    ],
                    "properties": {
                        "tenant": {
                            "title": "Tenant name",
                            "description": "The part that comes before .onmicrosoft.com OR your tenantID (GUID)",
                            "type": "string"
                        },
                        "id": {
                            "title": "Client ID",
                            "type": "string"
                        },
                        "secret": {
                            "title": "Client secret",
                            "type": "string"
                        },
                        "certificate": {
                            "title": "Client certificate",
                            "type": "object",
                            "required": ["thumbprint","privateKeyPath"],
                            "properties": {
                                "thumbprint": {
                                    "title": "Client certificate's thunbprint",
                                    "type": "string"
                                },
                                "privateKeyPath": {
                                    "title": "Path to the private key file",
                                    "type": "string"
                                }
                            }
                        }
                    }
                },
                "retryLimit": {
                    "title": "Times to retry sending a message when it failed",
                    "description": "Set to 0 to not retry (Default: 3)",
                    "type": "integer"
                },
                "retryInterval": {
                    "title": "Minutes between tries",
                    "description": "Default: 5 minutes",
                    "type": "integer"
                },
                "forceMailbox": {
                    "title": "Always send from this mailbox",
                    "description": "Must be a mailbox, can't be a distribution list",
                    "type": "string"
                }
            }
        },
        "receive": {
            "title": "SMTP config",
            "type": "object",
            "allOf": [
                {
                    "if": {
                        "not": {
                            "properties": {
                                "requireAuth": {"const": false}
                            }
                        }
                    },
                    "then": {
                        "required": ["users"]
                    }
                },
                {
                    "if": {
                        "properties": {
                            "tlsKeyPath": {"not": {}}
                        }
                    },
                    "else": {
                        "required": ["tlsCertPath"]
                    }
                },
                {
                    "if": {
                        "properties": {
                            "tlsCertPath": {"not": {}}
                        }
                    },
                    "else": {
                        "required": ["tlsKeyPath"]
                    }
                }
            ],
            "properties": {
                "port": {
                    "title": "SMTP server port",
                    "description": "The port on which the SMTP server will listen (default: 25)",
                    "type": "integer"
                },
                "listenAddress": {
                    "$ref": "#/definitions/ipaddress",
                    "title": "Listen for connection on a specific IP",
                    "description": "Default: all addresses"
                },
                "secure": {
                    "title": "Require a secure (TLS) connection",
                    "description": "When false, clients can still upgrade to a secure connection (default: false)",
                    "type": "boolean"
                },
                "tlsKeyPath": {
                    "title": "Path to a key file for secure connections",
                    "type": "string",
                    "required": ["tlsCertPath"]
                },
                "tlsCertPath": {
                    "title": "Path to a certificate file for secure connections",
                    "type": "string",
                    "required": ["tlsKeyPath"]
                },
                "maxSize": {
                    "title": "Maximum message size",
                    "description": "Only accepts string ending with 'k' (Kilobytes) or 'm' (Megabytes). Default: 100m",
                    "type": "string",
                    "pattern": "^\\d+[mMkK]$"
                },
                "banner": {
                    "title": "The banner being shown when a client connects to the STMP server",
                    "type": "string"
                },
                "ipWhitelist": {
                    "title": "IP addresses that are allowed to connect",
                    "description": "This can contain single addresses or subnets in CIDR format (eg. 192.168.1.0/24)",
                    "type": "array",
                    "items": {
                        "type": "string",
                        "anyOf": [
                            {"$ref": "#/definitions/ipaddress"},
                            {"$ref": "#/definitions/ipCIDR"}
                        ]
                    }
                },
                "allowedFrom": {
                    "allOf": [{"$ref": "#/definitions/emailArray"}],
                    "title": "Accepted FROM addresses",
                    "description": "Only accept those addresses as FROM addresses"
                },
                "allowInsecureAuth": {
                    "title": "Allows authentication even if connection is not secured first, when tlsKeyPath and tlsCertPath are set",
                    "description": "Default: false",
                    "type": "boolean"
                },
                "requireAuth": {
                    "title": "Require login",
                    "type": "boolean"
                },
                "users": {
                    "title": "SMTP users",
                    "type": "array",
                    "items": {
                        "properties": {
                            "username": {"type": "string"},
                            "password": {"type": "string"},
                            "allowedFrom": {
                                "allOf": [{"$ref": "#/definitions/emailArray"}],
                                "title": "Accepted FROM addresses",
                                "description": "Only accept those addresses as FROM addresses"
                            }
                        },
                        "required": ["username","password"]
                    }
                },
                "rateLimit": {
                    "title": "Limit the number of accepted connections over a certain time period",
                    "description": "Default: 10000 per 10 minutes (equals the Graph API's limit)",
                    "type": "object",
                    "properties": {
                        "duration": {
                            "title": "Time period in seconds",
                            "description": "Default: 600 (10 minutes)",
                            "type": "integer"
                        },
                        "limit": {
                            "title": "Maximum number of connection in the time period",
                            "description": "Default: 10000",
                            "type": "integer"
                        }
                    }
                },
                "authLimit": {
                    "title": "Limit the number of failed authentications per IP address over a certain time period",
                    "description": "Default: 10 per 1 minute",
                    "type": "object",
                    "properties": {
                        "duration": {
                            "title": "Time period in seconds",
                            "description": "Default: 60 (1 minutes)",
                            "type": "integer"
                        },
                        "limit": {
                            "title": "Maximum number of failed authentications in the time period",
                            "description": "Default: 10",
                            "type": "integer"
                        }
                    }
                }
            }
        },
        "httpProxy": {
            "title": "Use HTTP proxy",
            "type": "object",
            "required": [
                "host",
                "port"
            ],
            "properties": {
                "host": {
                    "title": "Hostname or IP for the proxy",
                    "type": "string"
                },
                "port": {
                    "title": "Proxy port",
                    "type": "integer"
                },
                "protocol": {
                    "title": "http or https (default: http)",
                    "type": "string",
                    "oneOf": [
                        {"const": "http"},
                        {"const": "https"}
                    ]
                },
                "username": {
                    "title": "Username for proxy authentication",
                    "type": "string"
                },
                "password": {
                    "title": "Password for proxy authentication",
                    "type": "string"
                }
            }
        }
	}
}