Hi there!
Is it possible for Mikrotik to send the date and time in the message field to greylog?
Remote logging in RouterOS is very primitive. Your only selection is the bsd-syslog flag which unfortunately changes different things at the same time, and no really desirable option is available.
This is a wishlist item for many years, so don’t hold your breath.
This may very well be possible to achieve on Graylog itself, with pipelines or lookup tables. I’ve played with both a little bit, but it’s not something I’m overly comfortable with using. I’m just curious though, what would the use case be for something like that?