dhcpd.conf fails to push options to fixed-address clients

[Simon]

Kenneth Porter <shiva at sewingwitch.com> wrote:

> There seems to be an issue with the options not fitting in the packet, because I had declared a filename for booting. I commented that out and now I'm seeing more options packed into the packet, including the lease time, netmask, gateway, and NTP server.

I’d never have thought of that, but yes it’s a problem I now recall having seen mentioned in the past.

> But the device is still repeatedly sending requests every 30 seconds, ignoring the configured lease time. That's a bug for TP-Link to deal with.

It may be because it’s not getting what it wants - therefore keeps trying.
Vendors can do some “interesting” things. Many years ago (at work) we got what was then a new-fangled digital copier with network printing - but I could never get it to take an address via DHCP so ended up manually configuring it. Quite by chance, some time later I read that it would refuse a lease of less than 2 years ! I never actually tested it, but that’s what I found (in a technical/service manual IIRC).

Looking back again at your config, it doesn’t look like a lot of long options. Perhaps you might try trimming down other stuff (e.g. trim off the second address for NTP and DNS) until the response can hold all the requested options and see if that makes any difference. Also, IIRC there’s a config declaration to increase the max size of the response packet - though using that can cause its own problems (packet not fitting in buffers built for standard sized packets).

Simon