@Amr_Ali If you are referring to NTP and DNS so that it can use those services it will use whichever interface has a route to reach the destination IP. You can configure your management interface with a management default but I recommend adding in static routes for destinations that you would like to reach from the management interface and leave your default route on the main routed interfaces of the F5, the ones you would use for virtual servers. The only gotcha on DNS is if you have a forward proxy virtual server configured the F5 will send traffic for DNS requests associated to hosts using the forward proxy out of its routed interfaces and not the management interface, even if you have a route telling it to go that way. I'm sure some other gotchas exists but that's the only one that comes to mind currently.
