Here is what I found setting up DNS clustering. Lets say I have server G.domain.com and A.domain.com I went into WHM on G and set up clustering. I copied the access key of A into the interface and voila, the clustering is set up. I choose "synchronise changes" in the interface and everything seems ok. I go to A and choose clustering as well but do not copy any access key in there or do anything else. G shows up as "standalone". So far everything seems ok, but just wait: Now I do a change for a zone on G and it is replicated to A - just as it should be. The just to test I go to A and do a change for a zone and guess what? The change is replicated to G!!!!! This is wrong and should not happen since I chose "standalone" and never even copied an access key of G into the interface on A!!! This is a major security bug and should not happen. If server A trusts server G then that does not mean G automatically trusts A!!!!!!! And it seems the setting of synchronise changes or standalone have no impact whatsoever! I highly recommend for Nick to fix this asap! So beware doing DNS changes on a standalone server and wonder why they replicate if they should not.