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# MDaemon Email Server 26.0

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Automatic Gateway Creation | Scroll Prev Top Next More

Automatic Gateway Creation

This feature is used to automatically create a Domain Gateway for a previously unknown domain when another source attempts to deliver that domain's messages to MDaemon, and a DNS query lists MDaemon's location as a valid MX record.

For example:

With automatic gateway creation enabled, if MDaemon's Default Domain IP address is 192.0.2.0 and a message is delivered via SMTP for an unknown domain example.com, MDaemon will perform MX and A-record queries on example.com to see if 192.0.2.0 is a known mail relay host for it. If the results of the DNS queries state that MDaemon's IP address is a valid MX host for example.com then MDaemon will automatically create a new Domain Gateway for it and accept its email. Messages for example.com will then be stored in a special folder and, if you so choose, spooled to higher level MX hosts at each remote mail processing interval. This feature effectively enables you to become a backup server for another domain by simply configuring the DNS system to use your IP as an alternate MX host.

To help secure this feature, MDaemon can be configured to send a confirmation request to an email address of your choice. While MDaemon is waiting for the confirmation response, messages for the domain will be accepted and stored but not delivered. Confirmation requests must be replied to within an amount of time that you designate or the automatically created gateway will be removed and all stored messages deleted. If confirmation is received before the time has expired then the stored messages will be delivered normally.

| It might be possible for a malicious person or "spammer" to attempt to exploit this feature by configuring their DNS server to list your MDaemon's IP address as one of their MX hosts. Automatic Gateway Creation must therefore be used with caution. To aid in preventing possible exploitation we recommend utilizing the Send creation confirmation message to... feature whenever possible.

Automatically create gateway domains

Click this checkbox if you want MDaemon to automatically create Domain Gateways based upon the results of DNS queries.

Use this existing gateway as a pattern

Choose a Domain Gateway from this drop-down list and MDaemon will use its settings as a template for all future automatically created gateways.

Don't create domain gateways when sender of message is a local user

Enable this control if you do not want messages originating from local users to trigger automatic gateway creation.

Don't create domain gateways when MX points to reserved IPs

Click this check box if you wish to prevent an automatic gateway creation when the MX record points to a reserved IP address such as 127.*, 192.*, or the like.

Require confirmation before rendering the gateway active

When this control is enabled, MDaemon will send a confirmation message to the email address of your choice in order to determine whether the automatically created gateway is valid. MDaemon will continue to accept messages for the domain in question but will not deliver them until confirmation is received.

Send creation confirmation message to

Use this text box to designate the email address to which confirmation messages will be sent.

Confirmation must be received within [xx] minutes

This control is for designating the number of minutes that MDaemon will wait for a response to any given confirmation message. If this time limit expires then the Domain Gateway in question will be deleted.

Deliver gateway's mail to higher MX hosts at each queue run

If you want MDaemon to attempt to deliver this gateway's messages to higher level MX hosts each time that the remote queue is processed then enable this control.

See:

Gateway Manager

MDaemon v26.0.0 - March 2026. Copyright © 1996-2026. All rights reserved. MDaemon Technologies