These messages are caused by the fact that in default configuration, the DHCP lease record (which station was assigned which IP address) are held only in the RAM of the router or switch. When you reload it, these leases are forgotten, and when DHCP server starts assigning IP addresses anew, it may try to assign an address that is already being used (assigned previously). Hence the messages.
The only solution is to configure a permanent storage for the leases. This is called DHCP Server Database. Information about this functionality and the configuration can be found, for example, here:
In short, the idea is to have the switch store these leases permanently to a network-accessible server via TFTP, FTP or HTTP. When the switch reloads, it downloads the stored leases file and continues assigning the addresses appropriately.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
Introduction Featured Speakers Luis Espejel is the Telecommunications
Manager of IENova, an Oil & Gas company. Currently he works with Cisco
IOS® and Cisco IOS XE platforms, and NX to some extent. He has also
worked as a Senior Engineer with the Routing P...
In this session you can learn more about Layer 3 multicast and the best
practices to identify possible threats and take security measures. It
provides an overview of basic multicast, the best security practices for
use of this technology, and recommendati...