reverse dns lookup problem

[Mark.Andrews at nominum.com]

	We are not mind readers.  If you want help show us the curtesy
	of not hiding the names and addreses involved.

	Mark

> Hi all Gurus,
> 
> we have a problem, regarding reverse DNS lookups *g*,
> reverse lookup (ip-number to host name) doesn't work for our domain.
> 
> On a small registered network (german telekom, ATM access
> 'T-interconnect', permanent connection, fixed IP, domain name registered
> at denic) we have our own nameserver, which after some trial and error
> does name resolution, as well as 'reverse DNS lookups'. using this
> server - also form outside - one can get name resolution hostname to ip,
> as well as ip to hostname. the same lookup using any other name server
> (denic, telekom, secondary telekom ns at uni-bielefeld) will resolve
> host names, but give 'non-existent host/domain' trying to resolve
> ip-number to host-name.
> it won't matter to us, but we are running in problems with foreign
> networks and mail systems which persist in reverse resolve before
> allowing access to their systems.
> e.g.
> *****
> from an machine outside on the net we do:
> nslookup
> default server: xxx
> address: yyy
> >server 'our-ns-ip-number'  # host name won't work reg. reverse -
>    lookup not working,
> default server: [our-ns-ip-number]
> address: our-ns-ip-number
> >our-server-host-name
> server: [our-ns-ip-number]
> address: our-ns-ip-number
> 
> name: our-server-host-name
> address: our-server-ip-address
> 
> >our-server-ip-number
> server: [our-ns-ip-number]
> address: our-ns-ip-number
> 
> name: our-server-host-name
> address: our-server-ip-address
> > exit
> *****
> this looks well to us, do you agree? the same procedure using telekom
> name server (pns.dtag.de), -with 'dig' and 'host' one can find our name
> server mirrored at this server! -
> *****
> from an machine outside on the net we do:
> nslookup
> default server: xxx
> address: yyy
> >server pns.dtag.de      # can use host name, reverse lookup working,
> default server: pns.dtag.de
> address: 194.25.0.125
> >our-server-host-name
> server: pns.dtag.de
> address: 194.25.0.125
> 
> name: our-server-host-name
> address: our-server-ip-address
> 
> >our-server-ip-number
> server: pns.dtag.de
> address: 194.25.0.125
> 
> *** pns.dtag.de can't find our-server-ip-address: Non existent
> host/domain
> > exit
> *****
> this looks less nice, doesn't it??
> 
> So, anybody any hint what went wrong??
> 
> Additional we have a problem with other customers working with dial on
> demand / internet by call with temporary ip numbers. running their own
> mail server, delivering mail directly to the addressee, the delivery is
> refused by some systems, errors like 'cannot find host for
> 'our-temporary-ip-number'' or similar. any hints, any help? it seems
> that more and more admins close their systems to cut down spam and
> hacking, so this problem will likely grow......
> 
> The systems are running linux, qmail, and show one more flaw, delivery
> to unkonown hosts will give instant errors, rejected deliverys are
> retried for about one week, letting the sender without success
> information. one workaround might be to deliver those mails relayed by
> our ISP, anybody done like this or has knowledge to teach about?
> 
> In answers please be 'verbose', from the above you can believe us to be
> total newbies.....................
> 
> many many thanks for every help.
> 
> Bernhard S. <test1test at my-deja.com>
> 
> 
> Sent via Deja.com http://www.deja.com/
> Before you buy.
> 
> 
--
Mark Andrews, Nominum Inc.
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at nominum.com