Question on DHCP HA

Hram Admin 60 Reputation points
2025-02-03T16:32:00.74+00:00

Hello!

Suppose the following DHCP configuration:

Lease duration - 8 days

HA:

01

According to MS's documentation

"DHCP1 provides an IP address lease to the client for the MCLT (not the full scope lease duration)."

0

Q: If "DHCP1 provides an IP address lease to the client for the MCLT (not the full scope lease duration)" then why do I always see the full-time (8 days) lease instead of my 30min lease?

Thank you in advance,
Michael Firsov

Windows Server
Windows Server
A family of Microsoft server operating systems that support enterprise-level management, data storage, applications, and communications.
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  1. S.Sengupta 22,006 Reputation points MVP
    2025-02-04T00:59:01.4966667+00:00

    The difference between the initial 30-minute lease and the final 8-day lease is due to the DHCP (HA) process. When DHCP1 assigns an IP, it starts with a short lease. After DHCP2 receives the binding update, it extends the lease to the full 8-day duration, ensuring a stable IP address for the client even in the event of a failover.

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  2. Hram Admin 60 Reputation points
    2025-02-04T19:06:30.49+00:00

    "it starts with a short lease." - the problem is that I do NOT see this "short lease" - any client gets the whole 8-days lease right upon its first OS start/reboot/ipconfig /renew - I've conducted several tests with various MCLT duration and all my clients got only 8-days long lease:

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