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Cisco Bug: CSCvs15759 - DHCP server sends out a NAK packet during DHCP renewal process.

Last Modified

Oct 02, 2020

Products (1)

  • Cisco Catalyst 9300 Series Switches

Known Affected Releases

cEdge-16.10.1 cedge-16.11.1

Description (partial)

During DHCP renewal process at 50% of the lease timer, Polaris device based DHCP servers are responding with a DHCP NAK instead of an ACK. This is causing devices to loose connectivity for microseconds and causing issues for some customers.

48  30.843586 -> DHCP 345 DHCP Offer    - Transaction ID 0x1b66
 49  30.845645 -> DHCP 358 DHCP Request  - Transaction ID 0x1b66
 50  30.846981 -> DHCP 345 DHCP ACK      - Transaction ID 0x1b66
189 216.118317 ->   DHCP 346 DHCP Request  - Transaction ID 0x1b66
190 216.119289 -> DHCP 342 DHCP NAK      - Transaction ID 0x1b66

Device Running Polaris code

DHCP Server config-

ip dhcp use subscriber-id client-id
ip dhcp subscriber-id interface-name
ip dhcp excluded-address
ip dhcp ping packets 1
ip dhcp pool 0
 lease 0 0 6
class-map match-any system-cpp-police-dhcp-snooping
  description DHCP snooping
 ip address dhcp
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