Questions

Core Reports Duplicate IPs

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Core Reports Duplicate IPs

jjf-88
The log in my core has been reporting a lot of duplicate IPs. We have 1000+ people on our network with a variety of BYOD devices. Every device is obtaining an IP from the DHCP server, which according to our systems admin nothing is wrong with the DHCP server. I need to find out why devices are obtaining an IP addresses that are already in use, and how I can minimize these duplicate IPs.
Please let me know if I need to be more specific.
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-gargravarr-

It could be that there is a "rogue" DHCP server on the network serving out address from the existing pool, seen this when a "hub" was stuck under someone's desk, it was actually a firewall with DHCP (not on the same subnet for my issue0. Check the DHCP lease times of the clients especially if they are BYOD and review how long they need to keep the lease before re-negotiating.
I'm assuming there's multiple IP subnets for these clients 1000 :0 and not a CIDR network.
look at DHCP snooping functionality on the core switches.