LAN Routing

L3 HP switch not preventing DHCP flooding

New Member

L3 HP switch not preventing DHCP flooding

Hello everyone,


I've an HP switch (HP 5400zl E5406 ZL - J8697A v2 with firmware K.15.17.0007) that I use as L3 switch to do inter-vlan routing for my LAN network.

Since it's supported, I also configured a DHCP server on it.


For some other firmware errors, I discovered I've two hosts on the network that keep asking new IP addresses to the DHCP server (every 5 seconds). I don't know why, the DHCP start to associate different IPs (at the same time!!) to the same MAC address, without never releasing (before the lease time expires) the addresses.

I've a lease time configured, so I really don't understand why this happens..


My config is the following:

dhcp-server pool "10"
   default-router ""
   dns-server ","
   lease 00:18:00


This is bad, since as soon as I turn on those devices the addresses in the DHCP pool finish in a second.


Count on your help!