Welcome, if you would like to post a comment please register.
We also encourage you to explore all things Zimbra with our team and members of the community.
Just for your information, it seems that with Google Apps there are similar problems, at least they do a one-time DNS SRV check when adding a domain to their service (ok, they have some more problems, as mentioned in the linked email, and please don't think I really want to compare Zimbra with Google Apps ).
Bugzilla
Wiki
Source
Similar problems with Google Apps 
).
Linear Mode
