Sample code for 30+ languages & platforms
Xojo Plugin

MX Lookup Mail Server Domain by Email Address

How to find the mail server for a given email address. Returns the domain name of the primary mail server.

Chilkat Xojo Plugin Downloads

Xojo Plugin
Dim success As Boolean
success = False

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

Dim dns As New Chilkat.Dns
Dim json As New Chilkat.JsonObject

Dim emailAddr As String
emailAddr = "bob@example.com"

// This gets all MX domains for an email address.  (Typically one domain.)
// The preferred domain will be at index 0 (see below).
success = dns.Query("MX",emailAddr,json)
If (success = False) Then
    System.DebugLog(dns.LastErrorText)
    Return
End If

Dim i As Int32
i = 0
Dim count_i As Int32
count_i = json.SizeOfArray("answer.mx")
While i < count_i
    json.I = i
    Dim domain As String
    domain = json.StringOf("answer.mx[i].domain")
    System.DebugLog(domain)
    i = i + 1
Wend