On 24-06-2019 02:38, A C wrote: > On 2019-06-23 11:08, Geert Stappers wrote: >> On Sun, Jun 23, 2019 at 09:33:21AM -0700, A C wrote: >>> On 2019-06-23 03:32, Geert Stappers wrote: >>>> On 23-06-2019 08:06, A C wrote: >>>> >>>>> I'm having trouble removing leases from my system. > I have: > > /etc/dnsmasq.conf: > read-ethers ###(there is a dash) > dhcp-range=10.0.200.100,10.0.200.105,255.255.0.0,12h > ### My netmask is actually 255.255.0.0 on the network, all dhcp leases > are in 10.0.200.x, static assignments are in other subnets > > /etc/ethers: > 00:25:9C:1C:0A:C3 ap.lan > ### and others > > /etc/hosts: > 10.0.0.252 ap.lan > ### and others > > >>>>> How can I fully purge the lease and get it to start over? The client is >>>>> an embedded device and has no memory of the lease once I power cycle it >>>>> so somehow dnsmasq is remembering even though the lease file was purged. >>>>> >>>> Recently I had simular sympthoms, infact still have them. >>>> >>>> >>>> My only issue is when I forget to add a client to the list >>>> prior to first putting it online and it acquires a lease from the DHCP >>>> lease pool instead of the IP I want to give it via the combination of >>>> ethers/hosts. After that I have extreme difficulty purging the lease to >>>> force a new address. >> My /etc/ethers has a line like >> >> 00:02:b0:ef:f0:ef kornuit >> >> Doing `host kornuit` returns correctly the IPv4 address that is in DNS. >> (other DNS as dnsmasq ( no kornuit entry in /etc/hosts )) >> >> >> I also stopped dnsmasq, removed the lease file and restarted dnsmasq. >> >> Did another PXE netboot ( consider it an embedded device, it has no >> memory of previous lease ) >> >> Server kornuit got the IPv4 address as before, one from the Dnsmasq >> DHCP range. Where it looks like a persistent DHCP lease, do I think >> that it is algoritme that hands out each time the same IPv4 address. >> >> Thing I need to verify is if dnsmasq does do a DNS-lookup on 'kornuit' >> after reading /etc/ethers.
Now using `dhcp-host=MA:CA:DD:RE:SS,192.0.2.42 > host ap.lan localhost (run on the same server as dnsmasq) returns > 10.0.0.252 as expected. > > Turned off the device, stopped dnsmasq, removed the lease from the lease > file, restarted dnsmasq and then restarted the device. I get the old > DHCP range lease instead of the one defined in hosts. > > If I add a host entry (with an IP outside of the DHCP range) and an > ethers entry for a device bore I ever plug it into the network I will > correctly get a static lease of the IP I define in hosts. If I forget > to do that, the device picks up a lease from the DHCP range and then > it's a massive fight to get rid of it. Sometimes I have to leave the > device disconnected for a few days so the lease expires on its own > (regardless of deleting the lease) and then I can switch the IP. > > There seems to be some kind of persistence that exists outside of just > the lease file but I don't know where that is. This isn't the first > time this has happened and it's happened with different embedded devices > and non-embedded devices (cameras, AP's, IoTs, phones, etc.) there just > seems to be sticky lease data somewhere. > You are probadly right about the "sticky lease data somewhere" (I'm not comfortable to say "you are right about sticky lease data" ) The lease file I removed had size of zero bytes. My (educated??) guess is that lease data is stored in Dbus. My only point to back that up, is `dnsmasq -v` showing "DBus" Cheers Geert Stappers
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