On Sun, Jan 14, 2007 at 08:59:21PM -0600, Seth Goodman wrote:
For many hosts, scattered around, the following could help:
"v=spf1 exists:%{ir}._spf.example.com -all"
That's not a realistic answer, but it is another way to do it.
Why wouldn't this be realistic?
- a list of authorized email hosts is kept in some database.  Any front
  end to edit this database will do, so managing the information should
  not have to be difficult
- this database is used by the DNS server.  Many DNS servers know how to
  process databases, and _spf.example.com can be in its own zone for those
  cases where the main DNS database needs to stay "as is"
- clients (processing the SPF record) need to do just one query extra, as
  opposed to multiple levels of "include". See hotmail
One disadvantage I can think of is buggy support for macros in SPF clients.
"%{ir}" will not be tested as much as "ip4" has been.
You say "not realistic".  Please elaborate, list some disadvantages which
make you say what you did.
TIA
Alex
-------
Sender Policy Framework: http://www.openspf.org/
Archives at http://archives.listbox.com/spf-discuss/current/
To unsubscribe, change your address, or temporarily deactivate your 
subscription, 
please go to http://v2.listbox.com/member/?list_id=735