AzureDeployment.json

{
    "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
        "zoneName": {
            "type": "string",
            "metadata": {
                "description": "The name of the DNS zone"
            }
        },
        "forwardingServerIp": {
            "type": "string",
            "metadata": {
                "description": "The IP of the server (to replace with a deployment of the server in this template)"
            }
        },
        "serverKey": {
            "type": "string",
            "metadata": {
                "description": "The DKIM key of the forwarding server"
            }
        },
        "forwardAddress": {
            "type": "string",
            "metadata": {
                "description": "Email address to forward the email to"
            }
        }
    },
    "resources": [
        {
            "type": "Microsoft.Network/dnszones",
            "name": "[parameters('zoneName')]",
            "apiVersion": "2016-04-01",
            "location": "global",
            "properties": {}
        },
        {
            "type": "Microsoft.Network/dnszones/A",
            "name": "[concat(parameters('zoneName'), '/mail')]",
            "apiVersion": "2016-04-01",
            "location": "global",
            "dependsOn": [
                "[parameters('zoneName')]"
            ],
            "properties": {
                "TTL": 3600,
                "ARecords": [
                    {
                        "ipv4Address": "[parameters('forwardingServerIp')]"
                    }
                ]
            }
        },
        {
            "type": "Microsoft.Network/dnszones/TXT",
            "name": "[concat(parameters('zoneName'), '/@')]",
            "apiVersion": "2016-04-01",
            "location": "global",
            "dependsOn": [
                "[parameters('zoneName')]"
            ],
            "properties": {
                "TTL": 3600,
                "TXTRecords": [
                    {
                        "value": [
                            "[format('v=DKIM1; k=rsa; p={0}', parameters('serverKey'))]",
                            "[format('forward-email={0}', parameters('forwardAddress'))]",
                            "[format('v=spf1 a mx include:mail.{0} -all', parameters('zoneName'))]"
                        ]
                    }
                ]
            }
        }
    ]
}