From: "David" <david(_at_)ols(_dot_)es>
Hi !!
Looks like blueyonder is an ISP. They need to be a bit more restrictive
with their record, listing only the approved outbound mail servers,
rather than the entire network including DSL nodes.
Blueyonder is one of the two or three cable ISPs in the UK. Every
subscriber gets a blueyonder email address, but it's fine for them
to send directly.
i don't feel that this is ok, spf enabling all their cable users means
that any zombie computer in this zone can start forging their emails,
it also allows any user to start using other's users email addresses,
which is totally opposite to spf idea as there is no guarantee that
any email comming from this isp was really sent by the real owner.
In fact there is no reason to trust that emails comming from this
isp has not been forged, as opossite from isp's that only publish
spf records for hosts that use smtp auth to authenticate their users.
Technically, you're quite correct. Politically and socially, it's a serious
problem. This is a *BIG* issue among my "Internet libertarian" friends. They
absolutely do not want their ISP's interfering in any way with their home
connectivity, and deeply resent any attempts to filter popular virus ports,
force the use of the ISP's SMTP servers for outgoing email, etc., etc. I've
encountered it professionally as well. People get extremely upset when you
attempt to put any kind of filters on outgoing mail, whether their
objections are well-founded or not. It's why it's so important to have the
more graceful ways to do things up and running and ready to go. For SPF use
for these people, this means that the insistence on PTR records matching the
A record for the IP is infeasible: they can register a domain trivially, but
getting PTR records for home use is quite expensive.
In my book, when they pay the triple price needed to pay the support staff
who have to deal with all the debris, they can have full unfiltered
connections. But for typical home connectivity, such a wide open and
unfiltered pipe is unnecessary and inappropriate.