Dynamic DNS with secondary nameserver?

[Sean Thomas Caron]

Hi folks,

We have an ISC DHCP server here feeding dynamic DNS updates to a BIND  
9 machine and it has generally been working fine.

Now I am trying to add a slave nameserver to the zone and it works  
fine for the static hosts but none of the dynamic DNS updates seem to  
propagate to the slave.

On the master, I have the dynamic sub-domain configured as follows:

zone "ddns.sph.umich.edu" in {
     type master;
     file "/etc/bind/ddns.sph.umich.edu.hosts";
     notify yes;
     allow-update { key dhcpupdate; };
};

This works great; the DHCP server feeds updates to the primary DNS  
server, no problem.

On the slave, I set it up as so:

zone "ddns.sph.umich.edu" in {
     type slave;
     masters { 141.211.51.166; };
     notify no;
     file "/etc/bind/ddns.sph.umich.edu.hosts";
};

When a host comes up on DHCP, the primary server picks it up fine:

> server 141.211.51.166
Default server: 141.211.51.166
Address: 141.211.51.166#53
> sph-2006-0090-test.ddns.sph.umich.edu
Server:		141.211.51.166
Address:	141.211.51.166#53

Name:	sph-2006-0090-test.ddns.sph.umich.edu
Address: 141.211.11.190
sph-2006-0090-test.ddns.sph.umich.edu	text =  
"31ce446f626045a4f8fe4933f448b613c6"
>


But it never seems to propagate over to the slave:

> server 141.211.51.66
Default server: 141.211.51.66
Address: 141.211.51.66#53
> sph-2006-0090-test.ddns.sph.umich.edu
Server:		141.211.51.66
Address:	141.211.51.66#53

** server can't find  
sph-2006-0090-test.ddns.sph.umich.edu.sph.umich.edu: SERVFAIL
>

I used 'rndc freeze' on the DDNS sub-domain then edited the zone file  
to have a really short refresh interval:

ddns.sph.umich.edu	IN SOA	dns.sph.umich.edu. hostmaster.sph.umich.edu. (
				2007024409 ; serial
				3600       ; refresh (1 hour)
				1800       ; retry (30 minutes)
				2419200    ; expire (4 weeks)
				86400      ; minimum (1 day)
				)


Then re-enabled it with 'rndc unfreeze' but it still doesn't seem to  
have made a difference. Even after waiting an hour, the additions to  
the dynamic DNS zone never propagate to the slave. I'm not even sure  
if those values are honored when dynamic DNS is enabled.

Most sites that I have seen discussing dynamic DNS only use one DNS  
server, so I am not exactly sure how this should be set up, or if this  
was ever intended to work this way. Is it possible? Or should I just  
make only the master a NS for the dynamic subdomain and leave the  
slave for static stuff only?

I feel like if it was going to work, I have it set up correctly..

Thanks,

-Sean