DHCP stands still, how can this be?

Question

DHCP

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DHCP stands still, sometimes it flies up for a couple of seconds. You turn off the garland on the port - it normally starts counting down. What is it in general can be and how it can be caught? Some kind of sniff? But what to catch?
The Internet does not work when the DHCP counter does not count.

Answer 1

Look at the logs, most likely the server sends the address to the client, but for some reason he does not receive it, the client requests the address again and the server again allocates the same address to him, resetting the lease time