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Sinichi_Kudo
Explorer
August 14, 2026
Question

FortiGate DHCP - 'Removed Due to Conflict' Issue

  • August 14, 2026
  • 2 replies
  • 123 views

We are experiencing an issue with our FortiGate DHCP server where IP addresses are repeatedly marked as "Removed due to conflict."

We have already performed the following checks:

  • Verified that there are no DHCP reservations or static mappings for the affected IP addresses.
  • Confirmed there are no duplicate static devices configured on the FortiGate.
  • Changed the DHCP IP range to a new subnet/range.

Despite these changes, the issue still occurs and clients continue to receive the "Removed due to conflict" message.

Could you please advise what else we should check or how to permanently resolve this issue?

Thank you.

2 replies

sjoshi
Staff
Staff
August 14, 2026

you may refer below article:

 

Thanks, Salon
farhanahmed
Staff
Staff
August 14, 2026

“Removed due to conflict” means the client detected an ARP response for the offered IP and sent a DHCPDECLINE, or the FortiGate received an ICMP response during its pre-offer check.

Please capture ARP, ICMP, and DHCP traffic and run the DHCP server debug to identify which MAC address is responding. Also check for overlapping IP pools with arp-reply enabled, proxy ARP, another DHCP server, or affected clients using docking stations. Once the responding device/configuration is identified and corrected, clear or allow the conflicted leases to expire.

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