gtm irule and persistence fails?

HI,

 

I have a very simple irule on the GTM that checks if the request is internal or external and based on that returns the internal pool or external pool..

 

 

when DNS_REQUEST {

 

if { [IP::addr [IP::client_addr]/12 equals "172.16.0.0"] } {

 

pool internal_pool

 

} else { pool external_pool }

 

}

 

 

At the pool level I have static persist using (/16 as the mask) for the LB type;

 

 

I do a curl to the page that displays the host name and I see the host name jumping between data centers...

 

 

Thoughts?

 

 

Thanks,

 

Jay