Problems with DNSExpress, WideIPs and master DNS

We have been having some DNS resolution issues with some WideIPs configured on our GTM.

 

The problem only occurs for subdomains, so for exmaple test.mysite.com will have resolution troubles, but not mysite.com

 

 

So our setup is as follows:

 

We have WideIPs configured for the servcies we need to have globally load balanced.

 

For everything else we use DNSExpress, so we have a master DNS server (PowerDNS) which is where we add all the other records we need.

 

We then create a slave DNS connection between our GTMs and the master DNS server. On the DNS express side, we just add the top level domain, so just mysite.com, and all the other records go to the master

 

 

The problem is that unless we add the wideIP to the master DNS server we get intermittient resolution issues.

 

If the WideIP is not configured on the master DNS server name resolution fails about 50% of the time. If we have multiple servers on a WideIP we can just add one IP address and it will still do the GLB we require, it seems that we just nee to have some type of entry in the master DNS server.

 

Anyone have any idea why this is happening? I have a case raised with F5 but they don't seem to understand.

 

I think it might have something to do with the SOA records, on the GTM it hasn't created any zones in zone runner, other than things like .com .net and the others...

 

Just not sure how SOA and DNSExpress ties in since we have all our SOAs on the master....

 

Any help would be greatly appreciated.