--On Dienstag, Mai 11, 2004 02:30:29 -0700 Daniel Quinlan
<quinlan(_at_)pathname(_dot_)com> wrote:
[...]
I concluded that yes, there sometimes may (and perhaps should) be a
significant delay between the receipt of an email and the SPF check.
You should retrieve the relevant SPF records as soon as you receive the
mail. There are providers who switch reverse DNS for dynamically assigned
addresses depending on the reseller with whom the customer has a contract.
Also dynamic DNS services might be used to set or erase DNS RRs for macro
evaluation when the customer connects or disconnects respectively. One
might even write a custom DNS server that queries the radius server whether
that IP address is currently used and by whom and thus delvier appropriate
SPF records.
If you delay evalution that needs information about the IP address used,
then you will get into trouble anyway. So I see no need to extend SPF to
include a timestamp.
Ralf