Inconsistent renews from F/O peers

Mark Sandrock sandrock at
Tue May 12 13:25:18 UTC 2015

> On May 11, 2015, at 11:20 AM, Shawn Routhier <sar at> wrote:
> Another item to check is if dhcp-cache-threshold is enabled on both servers.
> This is a feature to limit the number of times the servers touch the lease file.
> If a client requests a renew early instead of handing out a full lease the server
> simply hands out the previous lease again, correcting the lease time it sends 
> as necessary.  ...

So, dhcpd.conf(5) gives a default of
25% for 'dhcp-cache-threshold',
which contradicts what I am seeing.

The issuing F/O (primary) peer indeed
ACKs a 3597 in response to the renew,
but at the same time, (as the 3-second
renew is broadcast), the secondary
F/O peer ACKs an 86,400 value,
i.e., extends the MCLT lease time.

This seems like incorrect behavior
on the part of the F/O peer.

Thank you.

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