Julian Mehnle wrote on Sunday, January 14, 2007 4:06 AM -0600:
Not wanting to comment on the SPFv3 proposal as such, but... Don't do
that! Don't write proposed SPFv3 syntax using the "v=spf1" tag! This
runs the risk of confusing newbies endlessly!
Good point. An example of a three-IP non-contiguous range is:
"v=spf1 ip4:192.168.0.1 ip4:192.168.0.3 ip4:192.168.0.5 -all"
"v=spf3 192.168.0.1 192.168.0.3 192.168.0.5 -all"
There's no need to remove the old notation, just add this as short-cut. The
ip4: mechanism does make the parser's job easier, though I can't think of any
immediate conflicts and the result is slightly easier to read for humans.
We could save quite a few more characters for contiguous IP's that don't align
with bit masks. Frank correctly pointed out that ":" cannot be used as a range
separator because of ipv6. He suggested ".." and I also believe that "-" would
work. The range of six contiguous addresses from 192.168.0.5 through
192.168.0.10 using current spf1 and the proposed notation looks like:
"v=spf1 ip4:192.168.0.5 ip4:192.268.0.6/31 ip4:192.268.0.8/31 ip4:192.168.0.10
-all"
"v=spf3 192.168.0.5-9 -all"
The spf1 example assumes that the domain owner was clever enough to realize
that there are two /31's buried in this range. If "-" as a range separator at
the end of a dotted quad is a problem, we could use Frank's ".." suggestion.
Though I don't see any fatal flaws, I hope some of those who have written SPF
parsers will comment.
--
Seth Goodman
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