Opened 5 years ago

Last modified 4 years ago

#3888 new defect

Kea4 allows to rebind leases that is expired (extended rebinding state)

Reported by: wlodekwencel Owned by:
Priority: low Milestone: Outstanding Tasks
Component: dhcp4 Version: git
Keywords: Cc:
CVSS Scoring: Parent Tickets:
Sensitive: no Defect Severity: N/A
Sub-Project: DHCP Feature Depending on Ticket:
Estimated Difficulty: 0 Add Hours to Ticket: 0
Total Hours: 0 Internal?: no


According to RFC 2131 after lease is expired Kea should respond on DHCPREQUEST message, build for rebind state, with DHCPNAK and not assign leases. Kea behaves like rebinding state never ends.

Forge test


Attachments (1)

log_file (20.9 KB) - added by wlodekwencel 5 years ago.

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Change History (6)

Changed 5 years ago by wlodekwencel

comment:1 Changed 5 years ago by marcin

We should probably have closer look into this. However, I don't think this is a major problem. First of all, if the lease has expired, the client rebinds and the lease is still available there is not much harm in granting the lease to the client. Also note, that the client ends the rebind when it determines that the lease has expired and in such case the issue should not occur.

For Kea1.0 we will be implementing lease expiration. When this is implemented, the issue should naturally go away. I propose that we look into this ticket again after lease expiration is implemented.

comment:2 Changed 5 years ago by hschempf

  • Milestone changed from Kea-proposed to Kea1.0

comment:3 Changed 4 years ago by marcin

I don't really see this being an issue. For example: with the implementation of the RFC7550 we allow for allocating new leases in Renew and Rebind case. The server will also allocate a lease for which it doesn't have any record but the client is renewing it (if the lease is valid for the subnet to which the client is connected, obviously). Note that this may be the case when the server lost a lease it had allocated. I don't see us making up any special code that would discover that the client's lease has expired and not allow to rebind it. I think we should just close this ticket as 'won't fix'.

comment:4 Changed 4 years ago by stephen

  • Milestone changed from Kea1.0 to DHCP Outstanding Tasks

As per Kea planning meeting in October, remove from 1.0.

comment:5 Changed 4 years ago by tomek

  • Milestone changed from DHCP Outstanding Tasks to Outstanding Tasks

Milestone renamed

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