These posts ignited a lot of interest, and eventually led to the forming of the IETF Anti-Spam Research Group (ASRG) and their mailing list, where the SPF idea was debated among a subscriber base that seemed to grow exponentially day by day.
By performing an SPF lookup on incoming messages, MDaemon can attempt to determine whether or not the sending server is permitted to deliver mail for the purported sending domain, and consequently determine whether or not the sender When this option is enabled, MDaemon will perform a DNS query for SPF record data on each incoming message's purported sender, to ensure that the sending server is permitted to send messages on its behalf.
While it is not officially supported, we welcome any feedback you may have at .
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Disable this option if you do not wish to exempt authenticated sessions from SPF.
Click this option if you want all mail forwarded by MDaemon to use a local address in the SMTP envelope.