[Pdns-users] Difficulty changing nameservers on domain registar's site

SashaB topdomainerpro at gmail.com
Thu Jul 2 14:55:52 UTC 2009


I'm not sure what you mean. For example, so we didn't have to enter
different NS for 50 domains, I registered a domain name specifically for use
with NS (that is their sole purpose) and I've set up NS for multiple website
domain names that are identical--kinda like a webhosting company does? There
are four NS on two different servers at two datacenters in different parts
of a region (for which I haven't mirrored or set up round-robin yet, though
I intend to do so--and research shows I can on pdns). Actually, two of the
NS point to the same IP address as does the one in question and several
other NS point to that IP, too. All server diffent content--blogs, websites,
web interfaces for pdns, web guis for various applications, webmail
servers--just fine.

This works, in part, because the actual content is served, in most cases,
though not all, from an entirely different IP addresses from the NS IP
addresses (and the virtual host settings on apache reflect that). Yet, we
have no problem reaching any of that content, even where the NS IP address
are shared with content-serving hostnames rather than dedicated only to
doing NS resolution like other IP addresses. Again, domain resolution isn't
only about the nameservers--it's about the hosts and host.conf files, as
well as whatever backends we use, too. (There are some other factors, like
resolvers, but you get my point.)

So, as I explained, my mail/webmail NS are on different IP addresses under
its domain name from the content the webmail server and mail server
'serves'. All DNS records for the domain are contained on its master server,
including both NS, which point back to those IP addresses. The secondary NS
has it's own master record on the server where it's located and contains
only its IP address, since pdns doesn't use "pointer" records, relying
instead on it's native ability to resolve properly configured DNS.

Since I've created an "A" record for those IP addresses from which actual
content is served in the DNS records on our registrar's site (and have
properly configured the vhosts in apache), when we enter either our webmail
server IP address or its hostname, my webmail server software admin page
loads--just like it should.

When I load up the gui interface for our mailserver under either the
hostname, which is something like "mailservertype.maildomain.eu", it loads
perfectly. This stuff's fairly idiot proof because apache, mysql and pdns
all let you know when you've misconfigured stuff by not working right--or at

Therefore, I don't know how your answer relates to my problem and it doesn't
address the issue of the registrar not being able to reach the secondary NS,
which is on an entirely different server and has a separate IP address. This
doesn't appear, as you suggested when I posted my last question about how
PDNS works differently from BIND and again in this post, as my lack of
understanding DNS. I'm new to PDNS, not to DNS. I couldn't have set this
system up if I didn't have DNS understanding and the registrar for my other
domain names seems to have no problem adding our changed NS to their system,
so, our NS configuration aren't the problem.

If anyone else has any suggestions--especially those in the EU where this
seems to be an issue--at least when I bing(.com) it, I would greatly
appreciate your help.


On Thu, Jul 2, 2009 at 9:40 AM, Kenneth Marshall <ktm at rice.edu> wrote:

> On Thu, Jul 02, 2009 at 09:15:03AM -0400, SashaB wrote:
> > Hello all,
> >
> > This is a long post with a lot of info since I thought you should know as
> > much as possible about these NS before (a) having to ask the obvious
> > questions and (b) so you can offer suggestions.
> >
> > Here's the situation. I have set up the NS for our domains (on four
> servers)
> > and nearly all resolving properly to the domains to which they point.
> (For
> > those few that are not, I have figured out and corrected the issue; now
> > we're waiting for the changes to propogate.)
> >
> > However, we I have a specific domain registered via a registrar in the EU
> > for one of our mail/webmail servers and, each time I try to change the NS
> > (domain 'owners' can modify their own DNS on the registrar's site similar
> to
> > (but far simpler than) GoDaddy's "Total DNS"), I get the following
> errors:
> >
> > ns1.maildomain.eu  --->"The given nameservers return different SOA
> entries."
> > ns2.maildomain.eu --->"Connection to server failed."
> >
> > Before providing your help, you should know the following:
> >
> > 1) The nameservers are shared by other NS, all of which have domain names
> > associated for their specific purposes. (For example: ns1.foodomain.net,
> > dns1.thisdomain.com, ns1.maildomain.eu, etc.). I've pointed all "ns1"
> > domains to one IP address on each server and "ns2" are pointed to a
> > different IP address on each server but share the same IP address on that
> > server, etc.
> > 2) The NS for this domain are on different servers in the same region and
> > located in entirely different datacenters.
> > 2) While there is a master record for the ccTLD itself on its resident
> > server, I've also set up a separate master record for the NS1 so I can
> see
> > updating serial numbers for just the NS. Because I also set up, as a
> > supermaster, the hostname for the servers on which each of their NS has
> its
> > master record, without creating each NS as a slave on the master server
> for
> > that record, they each show on the other server as a slave and their
> serial
> > numbers (and my logs, which I've set up to view by secure webserver) show
> > they have been updating regularly.
> > 3) Websites and other applications, some with the same NS IP (but
> different
> > domain name), are resolving correctly.
> > 3) All NS point to IP addresses, not CNAMEs or redirects. In fact, I tend
> to
> > use IP addresses over hostnames because they resolve better if we make
> > changes to hostnames.
> > 4) I 'played around' with the NS to learn how pdns works and determine
> how
> > best to set them up, especially for security and convenience. In that
> > process, I found it was just easier to point the NS for all of our
> domains
> > to the same IPs on each server and use other IPs for other purposes (like
> > pointing a domain's webservers to). So, I changed the IP addresses for
> the
> > NS, deleted and recreated NS records, updated SOA records, etc. That may
> > affect the SOA entries.
> > 5) The NS have been live for at least 24 hours each.
> > 6) The NS point to different IPs from the domain's other records, like
> the
> > MX and webmail server, which have their own IP addresses. I've configured
> my
> > virtual hosts in apache accordinly (except I did not create any for the
> NS.)
> > 7) The SOA record of NS record on each server points to the appropriate
> IP
> > address and is configured, "ns1.maildomain.eu
> > hostmaster.masterrecordserver.com". Since each is on different servers,
> the
> > "hostmaster" domain name is for that server, not the master server (ns1)
> of
> > the domain itself.
> > 8) I've given the registrar's IP address access to my server (via
> > hosts/csf.allow and the firewall) and added its network address to the
> > 'axfr' setting in pdns.conf. The pdns-recursor is not active on one
> server
> > (configuration issues) but is on the other. On the server with
> pdns-recursor
> > running, each master record has a corresponding "in-address.arpa" entry.
> I'm
> > still working on that for the other server. Neither server, however, is
> > experiencing resolution issues with the domains not associated with these
> in
> > question.
> >
> > So, that all said, I have a few questions that might be a source of some
> > issues:
> >
> > 1) I've taken the extra step of creating an "A" record for each NS in the
> > domain's DNS settings on the registrar's site as well as updating the
> other
> > records for the domain in the registrar's DNS as well, thinking that may
> > help. Will that affect the SOA records?
> > 2) Do the changes I've made to the master records, i.e., changing the IP
> > address of the NS several times before deciding on a final configuration,
> > cause such problems? (The NS for my websites, which have totally
> different
> > NS, in part, so we don't have these issues with them, have been 'cast in
> > stone' for several weeks and haven't changed so they're resolving
> > correctly.)
> > 3) My understanding is that mysql acts as recursor when pdns-recursor.
> How
> > can I tell if the records in mysql are correct? (I've looked at the
> records
> > via Webmin but they don't contain full record entries or have IP numbers
> > associated, so I can't tell how accurate they are.)
> > 4) How does pdns-recursor and rDNS configuration affect resolution? Could
> > that be part of the issue?
> >
> > Finally, I've done searches online and found that others have this issue
> > with EU-based registrars. Ostensibly, this is to prevent NS
> > misconfiguration. But, I'm finding pdns is pretty good at that so I'm not
> > understanding the problem. But, since I have three more domains with this
> > registrar, I've got to so I can fix it. Please provide your
> > solutions-oriented assistance in trying to ressolve this issue so we can
> use
> > our own NS for our mail/webmail servers.
> >
> > If you've read this far, thank you and I look forward to your help.
> >
> > Sasha
> Hi Sasha,
> Thank you for the detailed description, but I think that the problem
> is described correctly by the error message you received from your
> domain registrar:
>    your nameservers have different SOA records (paraphrasing)
> All nameservers for a domain, by definition should have and serve
> identical content. I think that once you fix this inconsistancy it
> will all work.
> Regards,
> Ken
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