Hey everyone! I'm dealing with an ongoing IP conflict on my network and could use some help. Here's the situation: I'm not using a dynamic allocation pool for IP addresses; instead, I've fixed the IPs to the MAC addresses in my dhcpd.conf file. Despite checking the .leases file and finding it empty, a client device (MAC BB:BB:BB:BB:BB:BB) is struggling to obtain an IP address from our ISC DHCP server. The logs indicate a repeating cycle of DHCPREQUEST for xx.xx.xx.93, followed by DHCPACK from the server, then DHCPDECLINE from the client. This suggests that while the server is offering the IP, another device is responding to the ARP request, prompting the client to decline the IP to avoid a conflict. Upon investigation, I saw that a device with MAC AA:AA:AA:AA:AA:AA seems to be responding for xx.xx.xx.93, but it's correctly using a different IP (xx.xx.xx.141). I suspect it's a ghost IP issue where that device (AA:AA:AA:AA:AA:AA) is incorrectly replying to ARP requests for an IP it used previously. I've rebooted both devices (AA and BB), restarted the ISC DHCP service, and cleared the ARP cache on both devices, but the issue still persists. Pinging xx.xx.xx.93 results in a "request timed out". So, I'm really stumped. Any advice on how to resolve this?
1 Answer
Have you considered temporarily taking down the device you suspect is causing the conflict? That might help determine if the other device can successfully lease the IP. If it still doesn’t work, you might need to reassess and check if there's another device at play.
Thanks for your input! I’ve confirmed that the device with MAC (AA:AA:AA:AA:AA:AA) has two IPs assigned - one valid (xx.xx.xx.141) and the ghost (.93). I can access the workstation, and even after shutting it down and restarting, I still can’t use the .93 IP as it claims it's in use. A network scan shows both IPs and the same MAC.