mholm(_at_)medrad(_dot_)com wrote:
An A record assigns an IP address to a domain name. I believe the
erroneous "a:1.2.3.4" representation happens because people mentally
interpret the RHS of what comes after the ":" as that which is
assigned to the A record: an IP address.
The wizard that Microsoft sponsors:
http://www.anti-spamtools.org/SenderIDEmailPolicyTool/Default.aspx
asks the user to do exactly what you say is incorrect.
Does it?
<Direct quote from the page>
Enter any additional IP addresses (or ranges of addresses) you wish
to add to
your SPF Record (one address or address range per line).
Examples:
1.2.3.4
1.2.3.4/24
<End quote>
That quote is preceeded by this text:
"At present, the domain's A records contain the following addresses:"
It does NOT say: "A mechanisms" (which is correct). And when I enter an IP
address there, I get an "IPv4" mechanism, not "a" (which is correct):
v=spf2.0/pra ... ip4:1.2.3.4/24
Actually, lol, I get an "ip4" mechanism. :) But that aside,
Furthermore, the correct way of using a, all by itself, doesn't work
in this wizard, even though a check box to designate it is present.
The incorrect way is cheerfully passed through to the end result,
e.g. a:123.123.123.123
How did this occur? When I fill in the spot where it says:
"Enter any additional domain names you wish to add to your SPF Record (one
domain name per line),"
I (correctly) get:
v=spf2.0/pra ... a:teshost.com
Seems pretty much in order to me (though I could do without the
"v=spf2.0/pra"; but, hey, it is their Sender-ID wizard).
The Microsoft wizard, however, does (erroneously) NOT support:
a:colo.example.com/28
Which it SHOULD. Instead, you get an error:
"* One or more domain names have invalid syntax."
I don' think so. :) See:
http://spf.pobox.com/spf-draft-200406.txt
The wizard at http://spftools.net/create.php says:
<Direct quote from the page>
If there is another named host or subnet that can send mail from this
domain, enter it here, with the CIDR block size if appropriate:
(If you need to specify a host/subnet by IP address, please use an
IP4 record)
<End quote>
Now, if you know the meaning, this may seem clear, but when I read it
the first time, not really understanding, I read it as an invitation to do
exactly what you are complaining about.
That quoted text appears in the "Named Servers (A)" section. To my knowledge
of the current draft, I do indeed not believe that you can "specify a
host/subnet by IP address" is correct here. Not with an "a" mechanism, that
is.
Cheers,
- Mark
System Administrator Asarian-host.org
---
"If you were supposed to understand it,
we wouldn't call it code." - FedEx