Stephen Rose wrote: > Simon Kelley wrote: > >>I'm guessing that what happens is that the client sends a DHCPREQUEST to >>renew its lease and dnsmasq returns DHCPNAK: lease not found. The client >>then does DHCPDISCOVER-DHCPOFFER-DHCPREQUEST-DHCPACK and gets a new >>lease, but for the same address. (Checking the logs on the openWRT box >>will tell you if this is the case. >> >>My first reaction to this is that returning a DHCPNAK to an attempt to >>renew an unknown lease is the correct thing to do, and can't be changed, >>but when I actually looked at the RFC it wasn't clear that that's true. >>In fact, RFC2131 says almost nothing about sending a DHCPNAK to a client >>in RENEWING state. (It has plenty to say about SELECTING and >>INIT_REBOOT, but that's not relevant here.) >> >>As far as I can see, there are no bad consequences to just accepting a >>renewal of a previously-unknown lease, except in the case that the >>renewal is broadcast (ie rebinding) and picked up by both the correct >>server and another which happens to be on the same network. To avoid >>that, I would probably only change the behaviour when the >>dhcp-authoritative configuration is set, since that already has the >>meaning of "optimise for the case that I'm the only DHCP server on this >>network." >> >>I'll post a query about this to IETF mailing list. >> >>Cheers, >> >>Simon. > > > I checked the logs. That is indeed what's happening during the dialog > with Windows XP. I have a D-link access point that seems to need a > couple of DHCPREQUEST-DHCPNAK cycles before it finally decides to > DHCPDISCOVER. That device has an entry in both the ethers file and the > hosts file, so it can't get another address. At the very least, I would > expect devices that are pinned like that to not need leases. Just a > thought. > > Steve >
Feedback from the DHCP gurus was positive, so I've built a test version which should behave better under these circumstances (as long as "dhcp-authoritative" is set in /etc/dnsmasq.conf) I'll send you a copy by private mail, please could you test it? Cheers, Simon.
