Bind Software diversity

[Ladislav Vobr]

We have three public recursive servers serving large number of 
customers. I am purposely keeping software diversity among them. So I 
have one 8.3.4 and the other two 9.2.2.  I am even thinking of having 
different nameserver software to keep the code base diversity and make 
the system more resistant to different kinds of 
faults/errors/bugs/attacks. The factor of code diversity should be also 
considered, when recommending people to upgrade. Having all the 
nameservers the same, although latest release is not the best solution 
in my opinion. Any other experience with the similar setup. Shouldn't we 
think about running bind in combination with other solution, not because 
we prefer each other, but because it might be better at the end ? Or 
what is the opinion of the bind community ?

Ladislav