[Pdns-users] mx failure scenario

[Kelsey Cummings]

On Thu, Dec 21, 2006 at 10:40:09PM +0100, bert hubert wrote:
> On Thu, Dec 21, 2006 at 10:00:30AM -0800, gnu not unix wrote:
> 
> > I have a problem with my parent zone (sf.ca.us), where they
> > are running powerdns (they used to run bind), and this change
> > seems to have resulted in my loss of email connectivity.
> 
> Something definitely is odd:
> $ dig +norecurs -t mx wraith.sf.ca.us @B.AUTH-NS.SONIC.NET.
...
 
> This SOA record should not be there. I have no easy explanation why it is
> there.

Bert, it looks like PowerDNS is a little inconsistent about returning the
SOA along with delegation.  For delegations with glue it also returns the
SOA 

$ dig +norecurs -t mx kgctest.sf.ca.us @B.AUTH-NS.SONIC.NET.
...
sf.ca.us.               259200  IN      SOA     ns1.sonic.net.
hostmaster.sonic.net. 2006122104 3600 300 1209600 3600

Whereas if there is no glue, no SOA:

$ dig +norecurs -t mx kgctest2.sf.ca.us @B.AUTH-NS.SONIC.NET.

However, in any case if you actually ask for the SOA, you get the parent
zone's SOA.

$ dig +norecurs -t SOA kgctest.sf.ca.us @B.AUTH-NS.SONIC.NET. 
...
sf.ca.us.               259200  IN      SOA     ns1.sonic.net.
hostmaster.sonic.net. 2006122104 3600 300 1209600 3600

$ dig +norecurs -t SOA kgctest2.sf.ca.us @B.AUTH-NS.SONIC.NET. 
...
sf.ca.us.               259200  IN      SOA     ns1.sonic.net.
hostmaster.sonic.net. 2006122104 3600 300 1209600 3600

Bind, does not return SOAs for any of these queries which I belive is the
expected behavior - it just returns the NS records w/ or w/o glue as
appropriate.

>From what I can tell this does not adversely affect a bind recursive server
from being able to follow the chain of NS records correctly.  Whatever
problem wraith.sf.ca.us is having, I've seen nothing that suggests it has
anything to do with powerdns.
 
-- 
Kelsey Cummings - kgc at corp.sonic.net      sonic.net, inc.
System Architect                          2260 Apollo Way
707.522.1000                              Santa Rosa, CA 95407