Question about DHCP lease time

RouterOS General
1

Hi guys!

I have question for those of you, who use DHCP server on RouterOS platform (or maybe to RouterOS developers). All my servers are configured to give clients 1d long leases. Sometimes I see clients, mostly Windows machines, with short, 30 second lease time. After this short time the client lease disappears from leases. Where does this time come from? Is this a time when server sends DHCP OFFER and is waiting for DHCP REQUEST from client? Client, for some reason, doesn’t send DHCP REQUEST package, that is why server removes this lease? I need some short explanation :slight_smile:.

BTW, I use DHCP server with Radius authentication.

2

Also, there is no sign of such lease in LOG.

3

As I recall (it has been a while), the dhcp server will hold that lease offer for 30 seconds. If the client does not respond, then the IP is released. You can check that here:

/ip dhcp-server lease
print detail

It will show the status there also. I think it will say “offered” while waiting for a client to respond, and “bound” when the client does respond.