(VB.NET) DNS Query MX Records

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Shows how to perform a DNS query to retrieve MX records.

Note: This example requires Chilkat v9.5.0.96 or later.

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Dim dns As New Chilkat.Dns

Dim json As New Chilkat.JsonObject
json.EmitCompact = False

Dim success As Boolean = dns.Query("MX","somebody@gmail.com",json)
If (success = False) Then
    Debug.WriteLine(dns.LastErrorText)
    Exit Sub
End If


Debug.WriteLine(json.Emit())

' Sample response.
' Parsing code below..

' -------------------------------------------------------------------------------
' Note: Chilkat will return the results sorted by "pref" from lowest to highest.
' -------------------------------------------------------------------------------

' {
'   "answer": {
'     "mx": [
'       {
'         "name": "gmail.com",
'         "ttl": 491,
'         "pref": 5,
'         "domain": "gmail-smtp-in.l.google.com"
'       },
'       {
'         "name": "gmail.com",
'         "ttl": 491,
'         "pref": 10,
'         "domain": "alt1.gmail-smtp-in.l.google.com"
'       },
'       {
'         "name": "gmail.com",
'         "ttl": 491,
'         "pref": 20,
'         "domain": "alt2.gmail-smtp-in.l.google.com"
'       },
'       {
'         "name": "gmail.com",
'         "ttl": 491,
'         "pref": 30,
'         "domain": "alt3.gmail-smtp-in.l.google.com"
'       },
'       {
'         "name": "gmail.com",
'         "ttl": 491,
'         "pref": 40,
'         "domain": "alt4.gmail-smtp-in.l.google.com"
'       }
'     ]
'   }
' }

' Use this online tool to generate parsing code from sample JSON: 
' Generate Parsing Code from JSON

Dim name As String
Dim ttl As Integer
Dim pref As Integer
Dim domain As String

Dim i As Integer = 0
Dim count_i As Integer = json.SizeOfArray("answer.mx")
While i < count_i
    json.I = i
    name = json.StringOf("answer.mx[i].name")
    ttl = json.IntOf("answer.mx[i].ttl")
    pref = json.IntOf("answer.mx[i].pref")
    domain = json.StringOf("answer.mx[i].domain")
    i = i + 1
End While