wayne wrote:
That said, with the exception of the macro variables, the current SPF
format is very simple. Adding position dependant modifiers really
does increase the complexity of the SPF mini-language.
If you look at the SPF record as a script, then position-dependant modifiers
are not at all complex: If the parser encounters a mechanisn, it executes
it, and if the parser encounters a modifier, it stores the value. Very
simple. Only one pass is required.
But position-independant modifiers add quite some complexity to the parser.
The parser would have to first scan the SPF record for modifiers and store
their values and only then can do a second pass to execute the mechanisms.
Right now, there are no relations between the various
mechanisms/modifiers that
have to be kept track of.
I think that this is a bad idea. I should be possible to have several "exp"
modifiers.
Should modifiers be tied to the mechanism on the left or on the right?
Their value should be used for all mechanism on the right, until overridden.
All in all, I don't like position dependant modifiers very much.
But you like position-dependant mechanisms.
Other suggestions are:
Change the syntax of mechanism to allow for position dependant
modifiers. Something like "mx,scope=<blah>:domain.tld". Note that
this would currently parse as a modifier and thus would be ignored by
existing SPF implementations.
Use tags in the mechanisms, such as "mx.helo:domain.tld".
This does not work with current parsers.
Roger