I’m running a RB951 as default gateway with DHCP server for a small LAN.
If I’ve got a DHCP pool from 192.168.1.150 to 192.168.1.160 and one guy get address 192.168.1.155 from dhcp , then he set this address to his pc as static ip address.
Can it be possibile that my router would reuse the .155 with another client creating a problem?
It is safe to allow this behavior?
Thanks, BR
You can “cut” his IP address into a subnet 192.168.1.48/28(very generous) for his interface or create a static route into his interface to his /32 address 192.168.1.155 via your gateway IP(like Cisco unnumbered addresses). Or you can recreate dhcp pool without his 155 address.
Otherwise - no.
DHCP server indeed checks if the potential lease is already in use before leasing it out.
It sends out an ARP query to check. So this abvioulsy works that the client machine in question is on at that time. There’s only way to stop leasing this out other than Anumrak mentioned:
Create a static lease for this address, ideally with the correct MAC address for the client.
-Chris