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Question about DHCP lease time

Posted: Fri Nov 14, 2014 1:22 pm
by santa
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 :).

BTW, I use DHCP server with Radius authentication.

Re: Question about DHCP lease time

Posted: Fri Nov 14, 2014 2:44 pm
by santa
Also, there is no sign of such lease in LOG.

Re: Question about DHCP lease time

Posted: Fri Nov 14, 2014 3:18 pm
by SurferTim
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.