Convert non-ascii domain to SMTP compatible

Question

When customers enter email addresses with non-ascii chars like äüö our SMTP rejects to process them.

So I think might be there is a solution to handle those domains myself and convert them to punyocode.

Is there a simple way of doing so using c#?

Would this work anyway?

Answer 1

You can use Uri.DnsSafeHost to convert to Punycode:

using System;

class Test
{
    static void Main()
    {
        Console.WriteLine(ConvertToPunycode("caf\u00e9.com"));
    }

    static string ConvertToPunycode(string domain)
    {
        Uri uri = new Uri("http://"+domain);
        return uri.DnsSafeHost;
    }
}

In app.config:

<configuration>
  <uri>
    <idn enabled="All" />
  </uri>
</configuration>

Result:

xn--caf-dma.com