Retrieves the list of domain names for the specified IP address.

Parameters

ipString

The IP address string.

Return Value

The array of strings taken from DNS PTR data for the specified IP address, or a null reference (Nothing in Visual Basic) if an error occurred or no PTR record found for the given domain.

Remarks

This method makes DNS PTR query (reverse DNS query) to the servers listed in DnsServers collection regarding ipString address.

Popular anti-spam check is making reverse DNS query for the IP address from which the mail message was sent. Then, the retured domain name is compared with the domain name from "From:" or "Return-Path:" address to make sure it was really sent from that domain.

Note   If the IP address has multiple domain names associated with it, PTR record will usually return only the domain name taken from A record. Other domain names are aliases (CNAMEs). They will not be returned as their information is not contained in PTR records.

Exceptions

Example

This sample retrieves domain names associated with an IP address. Make sure to specify real IP address prior to running this sample.

[C#]
using System;
using MailBee;
using MailBee.SmtpMail;

class Sample
{
    static void Main(string[] args)
    {
        Smtp mailer = new Smtp();
        mailer.DnsServers.Autodetect();
        string[] domains = mailer.GetPtrData("123.123.123.123");
        foreach (string domain in domains)
        {
            Console.WriteLine(domain);
        }
    }
}

[Visual Basic]
Imports System
Imports MailBee
Imports MailBee.SmtpMail

Class Sample
    Shared Sub Main(ByVal args() As String)
        Dim mailer As Smtp = New Smtp
        mailer.DnsServers.Autodetect()
        Dim domains() As String = mailer.GetPtrData("123.123.123.123")
        Dim domain As String
        For Each domain In domains
            Console.WriteLine(domain)
        Next
    End Sub
End Class

See Also

Smtp Class | MailBee.SmtpMail Namespace | GetMXHosts | GetTxtData

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