On Mon, May 10, 2004 at 09:57:05PM -0700, Daniel Quinlan wrote:
| Meng,
|
| For the purpose of testing SPF accuracy on corpora (which is important
| to filters), it would be very nice if the SPF record could carry an
| optional date identifier signifying since when the record has been
| effective. Basically, meaning, don't bother trying to verify SPF mail
| sent before that date or time.
|
| It could be ISO date format (YYYY-MM-DD) or seconds since epoch.
|
| - Daniel
|
That is an intriguing suggestion which I had not considered before.
I can see the value of such an attribute for testing, but the protocol
was designed as an on-the-wire, realtime test. If we started down
this road, we might end up with an era syntax with different effective
SPF expressions during different date ranges, and that seems like too
much complexity. For corpus testing I suggest using the assumption
that an SPF record, if present in the DNS today, is likely to have
been valid for recent transactions within, say, a month.
How do people solve this problem for corpus-testing DNSBLs?