纯C#写的DNS相关组件，包括各种解析包括邮件交换器等。就是找不到下载的地方，下面是介绍！！

http://www.hallogram.com/keytechdns/


Query DNS servers for MX and other resource records.

Query DNS servers for MX and all the other resource record types defined by RFC-1034 and RFC-1035. The DNS .NET class library makes it easy to retrieve the list of configured DNS servers, construct a DNS query request using the convenient message and resource record classes, send the request to a DNS server and receive the fully parsed response. Written in 100% managed C# code, the class library offers .NET developers complete access to DNS resources from within their applications.

The DNS .NET class library may be used in any Windows or Web application by adding a reference to the assembly to access the classes in the KeyTech.Dns namespace.

The DnsMessage class models DNS request and response messages. It makes it very easy to construct DNS requests and access DNS responses. A separate class describes each resource record type. Each resource record class is derived from the ResourceRecord abstract class.

The list of resource record classes includes:
ARecord
CNAMERecord
HINFORecord
MBRecord
MDRecord
MFRecord
MGRecord
MINFORecord
A catch all OtherRecord
MRRecord
MXRecord
NSRecord
NULLRecord
PTRRecord
SOARecord
TXTRecord
WKSRecord

The DnsClient class allows you to send DnsMessage requests and receive DnsMessage responses. Within the DnsMessage request you specify the DNS questions to ask. The DnsMessage response contains the lists of ResourceRecords.

You may send requests from within DnsClient either synchronously (blocking) using the Send method or asynchronously (non-blocking) using the BeginSend and EndSend methods. Similarly, responses may be received either synchronously (blocking) using the Receive method or asynchronously (non-blocking) using the BeginReceive and EndReceive methods. For asynchronous calls you may receive completion notification either through an event or a callback method. A timeout may be specified.

All classes that raise events support a SynchronizingObject property. All classes report errors through the DnsException.
KeyTech ICMP .NET Features
Microsoft .NET, C#, VB.NET, ASP.NET and VS.NET compatible
Supports RFC-1034/RFC-1035
No complicated DNS message construction or parsing
Specify the resource types to retrieve including all
Retrieve the list of configured DNS servers
Calling applications may make either synchronous or asynchronous calls
Asynchronous calls may either use events or callbacks
Specify a timeout
100% managed code written in C#
Object oriented design specifically for the .NET framework
All error handling through .NET exceptions
Comprehensive Visual Studio .NET style documentation
VB.NET and C# example source code
Includes prompt free email support
Royalty free runtime

This product is Electronically Delivered.