I have been dealing with an issue caused by DirecTV.
Seems they are now making alternate connections and MACs in their boxes to the network. This is causing problems with control and streaming.
I need to be able to tell the box… get a new IP address now. So the router needs to deassign the IP from the MAC. Then I will use that same script to activate a dhcp reservation in the leases. So when the box requests a new IP it gets the assigned IP.
So I need to start with…
router deassign lease from MAC.
Use a short lease period - DHCP clients try to renew their lease at 1/2 of the lease period, so if you made your lease time 10 minutes, then the box would learn its new IP within 5 minutes of your change… There’s no way to tell a DHCP client that its IP has been revoked. If the box does a DHCP renew whenever its ethernet interface transitions from down to up state, then if it’s plugged into your mikrotik, you could shut down the interface for a few seconds, and when you re-enable the interface, it would send a dhcp renew…
If the shutdown/enable interface method works, then you don’t need low lease times.
And in general - don’t use low lease times if you have a lot of devices on your network - the low lease time recommendation is only sensible for a small home network.
Seem that there is no resonable answer: http://forum.mikrotik.com/t/dhcp-how-to-block-ip-offer-to-the-client/94331/3
Lease script is invoked by ROS after IP is assigned or deassigned so there is no way to make control it.
That sucks.
What I am seeing is that the boxes will find another way to get an IP address. I have seen them jump from using the RJ-45 to suddenly producing a DECA network. Nothing I can do there as the interface is the coax. Another installer reported a unit jumped on the wireless.
Whatever the case… log into Mikrotik
/ip dhcp-server lease
And there will be a MAC one off from the one I assigned to the IP.