Based on history from previous and successful requests, I shouldn't have needed to. They've fulfilled requests as vague as that in the past.
Submitted two requests two days ago that might be a bit better than providing the domains, though. One for DNS resolution logs of the mayor's office and another for all domains and times for all emails sent from their office. If just one of those are successful, then I don't need to play any more FOIA games with mayor's office.
Sure, I could just submit the same request to their IT department like those two... but, no. I'm getting that information from the mayor's office directly, dammit. :)