Re-ordering slightly ...
At 15:33 +0100 24/7/06, Ted Harding wrote:
Sorry to be puzzled!
No need to apologize ! You are stuff with trying to understand
several interlinked elements - and policies imposed by more than one
organisation.
On 24-Jul-06 Simon Hobson wrote:
[...]
I note that 88.96.44.206 resolves to 88-96-44-206.dsl.zen.co.uk so
the first thing you will need to do is get that changed to resolve to
something fixed and which you own - unless you do that then SORBS
isn't going to delist you.
Hi, Simon.
Many thanks for your comprehensive and detailed reply, and for
going to the trouble to dig into the SORBS web page for the info.
However, a lot of it is somewhat over my head! In particular,
the bit I quote above.
The issue that "88.96.44.206 resolves to 88-96-44-206.dsl.zen.co.uk"
is one which (in very similar terms) has been raised by a number
of people who have posted to the Zen support forum. One Zen reply
pointed to
http://www.zensupport.co.uk/knowledgebase/article.aspx?id=10166
which states:
Getting custom reverse DNS entries
In order to have custom rDNS set up you must e-mail details
of the records required to rdns.request@xxxxxxxxx
You should include your Zen username and you must be the
registered owner or administrator of the domain you will be
using with the rDNS entries.
For each of the rDNS entries you request there must be a
working, matching, forward record. The preferred format
for requests is as follows:
IP -> A-record
e.g.
1.2.3.4 -> mailhost.example.com
So I guess, combining that with what you said, Simon, I would
need to become "the registered owner or administrator of the
domain you will be using with the rDNS entries."
How the hell do I do that?
In simple terms, you must have a domain name of your own, eg you
might choose to register "tedharding.co.uk" (if it's available) to
use as a domain name.
After that, you might choose to say that your home (IP) address is
home.tedharding.co.uk.
So to satisfy Zen you would need to create "home.tedharding.co.uk A
88.96.44.206" as a DNS entry (the forward record). This you would do
by adding "home A 88.96.44.206" in the tedharding.co.uk zone via
whatever tools your DNS hosting service provides.
Once you have done this, you can get Zen to change the reverse record
so that 206.44.96.88.in-addr.arpa points to home.tedharding.co.uk -
ie there would be a record "206.44.96.88.in-addr.arpa PTR
home.tedharding.co.uk."
If you don't have a domain name THAT YOU CONTROL then there is
nothing sensible that Zen can set your reverse pointer to !
For example, it looks as though it would need MX records,
i.e. where to route mail to if addressed to a host on that
domain. Normally my mail goes to nessie, via whatever happens
to be doing duty as mailrouter.mcc.ac.uk (which at the moment
seems to be gannet). However, a "dig -mx nessie.mcc.ac.uk"
seems to point directly to nessie herself!
So is it legitimate to nominate nessie as MX host for my
private domain?
Yes and No !
From a DNS point of view, yes it is. However there are probably
policies and firewall restrictions in place that would stop it
working !
More importantly, for a 'diy' unblocking, SORBS is looking for an MX
record that matches the A record (don't know why, it's an arbitrary
restriction that isn't needed for mail to work). Thus you would need
to have "tedharding.co.uk MX 10 home.tedharding.co.uk".
Frankly, I think that when Zen (or other ISP) hands out a fixed
IP address,it ought to be trivial for them to register this as
such (and not a dynamic IP) with SORBS or other blacklist agency.
Zen has nothing to do with SORBS ! I very much doubt if Zen have
registered the address block with anyone (apart from RIPE of course
!) It's just a case of SORBS having worked out that this address
block is used by an ISP for dynamically allocated customers. The most
likely reason is that they've had spam reports, looked at the source,
and seen reverse DNS entries of the form "d.c.b.a.dsl.isp.net" which
is typical of dynamically allocated addresses.
If Zen are willing, there is probably nothing to stop them contacting
SORBS and getting you unlisted without having to point your MX at
your home address.
Finally, to give you some real examples, take a look at my DNS
entries. You'll find that primary mx for thehobsons.co.uk is
saffy.thehobsons.co.uk, saffy is at 81.174.135.208, and
81.174.135.208 resolves to saffy. Ie I have :
saffy.thehobsons.co.uk A 81.174.135.208
thehobsons.co.uk mx 5 saffy.thehobsons.co.uk.
208.135.174.81.in-addr.arpa ptr saffy.thehobsons.co.uk.
All my mail is handled by a Linux box at home.
Does that help ?
Simon
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