Re: [Sheflug] * on mail exchanger records

[nospam [at] alexhudson.com]

On Mon, Jul 23, 2001 at 05:09:11PM +0100, Dave Mitchell wrote:
> First off, its isn't quite as bad as you think - the only thing it will
> affect is mail servers - lynx and the like will be looking for A (address)
> records rather than MXes, so they wont be affected.

Yes; true. It does lead to interesting error messages though, usually with
the search domain appended on the end of the domain you were searching for,
which confuses users :(

> Second, most modern resolvers have a rule along the lines of: if the
> domain you're seaching for has at least 1 dot in it, look it up first
> *without* appending the default domain

I wasn't aware of this, except indirectly - I did notice that the resolver
seemed to be doing things in reverse (i.e., foo.com, foo.com.localdomain),
which I assumed meant that it was doing it in the correct order, and falling
back to foo.com.localdomain because it had at least retrieved a NOERROR,
even though there was no answer. Which didn't really seem logical to me; but
was the best I could think of!!

> However, I'd say the ISP are still in the wrong

Good, we agree :) What seems even strange is that they don't appear to
intend to catch everything, because the domain looks something like:

	foo.com		IN MX [their mail server]
	www.foo.com	IN A  [our web server]
	*.foo.com	IN MX [their mail server]

. which means www.foo.com doesn't have a mail exchanger. Unless that's
something they've not understood?

> So, tell your ISP to go take a hike, or to at least give a decent technical
> justication for their actions :-)

I tried asking for that and didn't really seem to be getting anywhere :(
Well - they agreed to take out the wildcard record. However, they didn't
really understand the problem I was having until about the fourth phone call
this afternoon. I gave them reams of examples; nslookup debug output;
allsorts. They just didn't appear to understand - for example, when I
illustrated the different between their server and records from another dns
server (this server is recursive) I got the response back "the other server
holds the authoratitive information for the domain linux.com, which was why
that didn't come back as an authoratitive answer from our server" - which
meant they had plainly _not_ _read_ my email to them. I get the feeling the
person in charge of their DNS server (the engineers I spoke to were all very
helpful) is a complete waste of time....

Cheers,

Alex.

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