One important thing we must do for an SMTP Server is to add reverse DNS record on our Cloud Service.

To do this, first of all, we must install Azure Powershell, WindowsAzurePowershell.

Now, we must execute the following commands in PowerShell:

Azure Service Management(ASM)

Add-AzureAccount
Select-AzureSubscription "subscription name"
Set-AzureService -ServiceName "mycloudservice" -Description "SMTP Server Reverse DNS Record" -ReverseDnsFqdn “mycloud.cloudapp.net”

If we want to correct, Reverse DNS Record, we must run the following command,

Get-AzureService "mycloudservice"

Azure Resource Management (ARM)

Login-AzureRmAccount -SubscriptionId "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"
Select-AzureRmSubscription -SubscriptionId "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"
$p=get-azurermpublicipaddress -name "Public IP Name"-resourcegroupname "Resource Group Name"
$p.dnssettings.reversefqdn = "domain name"
set-azurermpublicipaddress -publicipaddress $p