In IPv6, the T2 rebind timer fires at what percentage of the lease duration?

• A. 60%
• B. 70%
• C. 80%
• D. 90%

Answer: (C)

In DHCPv6, lease maintenance uses two timers tied to the lease duration: T1 for renewal with the original server, and T2 for rebinding with any available server if the original can’t respond. The T2 rebind timer fires at 80% of the lease duration. This timing provides a window to try rebinds before the lease actually expires—giving enough time for other servers to respond while avoiding waiting too late. If you waited longer (like 90%), there’s a greater risk the lease could expire before a successful rebind; if you triggered earlier (like 60% or 70%), it could waste resources by rebinding too soon. Therefore, 80% is the value that balances timely renewal with reliability.