DNS / Mail problem
Mark_Andrews at isc.org
Mark_Andrews at isc.org
Sat Dec 14 11:51:17 UTC 2002
>
> glederrey at swissonline.ch wrote:
>
> > Here is the DNS configuration :
> >
> > In the zone "genam.ch" :
> >
> > cobalt IN A 62.2.169.201
> >
> > In the zone "oppersdorff.net"
> >
> > von IN CNAME cobalt.genam.ch.
>
> so far so good.
>
> > Now there are two problems (maybe unrelated). First : when this client s
> > ends mail (Outlook, with her ISP's smtp server) the "From:" and
> > "Reply-to:" headers get rewritten from "user at von.oppersdorff.net" to
> > "user at cobalt.genam.ch".
>
> You say she's sending email from her ISP's smtp server. Okay. So why
> would the server rewrite anything? To me it sounds like a setting in
> her ISP's smtp server, though why, I can't tell you.
Well this is actually a RFC requirement. Aliases are supposed to
be re-written.
> > I dont have this problem with any other domain
> > that I host, but those domains have an MX record, and not a CNAME ; you
> > cant have both an MX an d a CNAME for the same name, that is the
> > following is wrong :
> >
> > von IN CNAME cobalt.genam.ch.
> > von IN MX 0 cobalt.genam.ch.
>
> You can. What you can't have is:
>
> von in cname cobalt.genam.ch.
> von in mx 0 von.oppersdorff.net.
Neither is legal. CNAME and other data is illegal. The other
data in this case is the MX record.
> because an mx record can't point to a host defined by a cname record.
>
> In your example, the mx is pointing to cobalt.genam.ch, which is defined
> by an A record, which is fine.
>
> > The question being : how can I avoid this header rewrite ?
Don't use a CNAME.
> Try putting in the cname, but I still don't see how it's got anything to
> do with the header rewrite. mx defines where mail is delivered to; it's
> got nothing to do with sending mail.
>
> > The next problem is that with this configuration, I need to have the
> > same host for the mail and for the web (Cant have both MX and CNAME). Is
> > there a better solution ?
>
> Just put in the cname record. You can.
No you can't. Please go read the section on aliases in RFC 1034
to understand why you can't.
> > I can declare von.oppersdorff.net as an A record, but that doesnt seems
> > "clean", if the web host moves, then I have to edit all DNS zones, and
> > not only the "main" one.
That is the way you do it today. Eventually you should be able to
use SRV records once the browser vendors add support.
> > I am probably missing something, or I have some of the concepts wrong.
>
> I think you've got some of the concept wrong.
No. You have the concept wrong.
Mark
> Jeff
> --
> Jeff Lasman, nobaloney.net, P. O. Box 52672, Riverside, CA 92517 US
> Internet & Unix/Linux/Sun/Cobalt Consulting +1 909 778-9980
> Our jblists address used on lists is for list email only
> To contact us offlist: "http://www.nobaloney.net/contactus.html"
>
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark.Andrews at isc.org
More information about the bind-users
mailing list