> Once the core value of SPF is understood, there'll be no stopping it!
Yup, and if you're right about the dynamic it'll unleash, pretty soon running
a "vanity domain" will be impractical thanks to ISPs tightening down their
mail server configurations.
vanity is a pejorative usage which implies the PTR hostname is somehow
superficial, inconsequential, optional, like vanity license plates (which
work just well no matter what the text is).
Many, and increasingly more, MX admins disagree, since they use the PTR
hostname as part of their DNS validations of sending MTAs.
If a PTR hostname is a generic hostname indicating a location in a
subscriber access network, then the chances are 99+% that the IP sending to
MXs is a compromised PC on a network not policed by the network operator
who allows subscriber IPs to connect to any port 25. Whether the reverse
zone is static or dynamic is irrelevant. So if a company is paying for a
static IP or subnet, it really needs to get the provider to change the PTR
away from the generic subscriber access network hostname.
Len
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