MX Component

The MX control enables querying of mail exchange (MX) records from a Domain Name Server (DNS). That is, it will find out the name(s) of the mail server(s) accepting email for a given email address or domain. (NOTE: The following is a very short description. For more information, please consult the help files that come with the respective package.)

The control will try to find out automatically the name of a DNS server from the system's settings and set the DNSServer property.

The control operates in asynchronous mode: assigning an email address or domain name to EmailAddress property directs the control to query the DNSServer and fire the Response event for each server which handles the mail for the email address and fill out the MailServer property with the most preferred mail server and the Status event to "Ok" or an error message.

RequestId may be used to identify requests and is used in the Response event. The user may set its value before sending out requests.

This control requires a Winsock 1.1 compliant TCP/IP stack. This means that the Winsock stack installed in the system must have a version of at least 1.1. In particular, Windows 95, 98, and NT machines with Winsock 2.0 are fully supported.

PROPERTIES

DNSPort. The port where the DNS server is listening.

DNSServer. IP address (or name) of the DNS server to query.

EmailAddress. Action property triggering a request to DNSServer.

MailServer. Mail server with lowest precedence value (lowest cost to reach).

RequestId. Identifies each request.

Status. Status of the request: empty while in progress, 'OK' or error message upon completition.

LocalHost. The name of the local host or user-assigned IP interface through which connections are accepted or initiated.

SocketHandle. The handle of the main socket used by the control.

WinsockInfo. Identifying information about the loaded Winsock stack.

WinsockLoaded. Loads and unloads Winsock on demand.

WinsockMaxDatagramSize. Size in bytes of the largest UDP datagram that can be sent or received.

WinsockMaxSockets. Maximum number of sockets available to a single process.

WinsockPath. The path to the Winsock DLL used.

WinsockStatus. The status of the Winsock stack.

EVENTS

Response. Fired for each MailServer accepting email for the domain.

Error. Information about errors during data delivery.