AirLive ES-6000 - Manual (Page 192)

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11.5 SPF (Sender policy FrameWork)
SPF (Sender Policy Framework) is a type of verification process that is used to prevent fake e-mail addresses
by identifying the authenticity of the e-mail sender and filtering out spam.
How SPF Works
To apply the SPF verification process, two important things must be done to both the sending and receiving
end of the e-mail.
1. The DNS server must be added a SPF record at sender end.
2. The Mail server must enable the SPF verification function into order to make SPF working. (Figure 11-5)
Figure 11-5 SPF setting
For example, suppose someone sends out a spam pretending to be an e-mail from AirLive mail server to your
e-mail address.
When this spam e-mail is sent to an account with SPF enabled, the account will ask AirLive mail server for the
SPF record based on the e-mail’s IP address to check if the IP really came from AirLive.
If AirLive mail server confirms the SPF verification, then the e-mail will pass the account’s SPF verification and
be sent to the receiver.
On the other hand, if the e-mail does not pass the SPF verification it shall be viewed as junk mail. This means
that even if the e-mail is really being sent out from AirLive, yet if AirLive mail server doesn’t provide SPF
record checking at that time, the e-mail that won’t go through the receiver account’s SPF verification will still
be viewed as junk mail.
The SPF checking process needs the sender account to set up SPF record to provide verification
checking in order to send and receive normally. It works best when more people use this verification
process to completely put the set up to use. The number of corporations that currently have SPF
record checking is still quite small, thus under this condition the SPF process at the receiving end that
filters out any junk mail will provide the sender with a great deal of inconvenience.