Hey - that worked! Setting my leases to 12 hrs fixed everything. Heh, I guess there are some subtleties in interpreting "infinite".
For completeness: # Old. not working. # dhcp-host=<livingroom_pc_MAC_redacted>,192.168.0.150,livingr oom.internal,infinite # New, working. # Diff: # - 12 hour lease, not infinite # - Don't even need the .internal suffix # Removed hosts file dhcp-host=<livingroom_pc_MAC_redacted>,192.168.0.150,[::0:1000],livingr oom,12h On Tue, Apr 21, 2020 at 1:54 PM Geert Stappers <stapp...@stappers.nl> wrote: > On Tue, Apr 21, 2020 at 09:57:34AM -0400, Jiawen Chen wrote: > > On Tue, Apr 21, 2020 at 3:06 AM Geert Stappers wrote: > > > On Mon, Apr 20, 2020 at 10:27:11PM -0400, Jiawen Chen wrote: > > > > > > > > I'm using dnsmasq for DHCP + DNS on my home LAN and use dhcp-host to > > > > statically assign an IP address and hostname. However, I'm > discovering that > > > > while it works most of the time, sometimes, ssh for example, can't > find the > > > > host by name, only IP. One instance is a Linux VM. Initially I can > ssh into > > > > the VM. But if I power down the VM for say a few days, and start it > back > > > > up, the name is missing (even though it is somehow assigned the same > IP (it > > > > keeps its MAC)). > > > > > > > > dnsmasq.conf: > > > > ``` > > > > # other irrelevant stuff > > > > ... > > > > # Assign 192.168.0.150 to my living room pc > > > > > dhcp-host=<livingroom_pc_MAC_redacted>,192.168.0.150,livingroom.internal,infinite > > > > > > > > # Assign 192.168.0.151 to my file server > > > > > dhcp-host=<fileserver_MAC_redacted>,192.168.0.151,fileserver.internal,infinite > > > > ``` > > > > > > I suggest to change the ',infinite' into something like ',12h' > for > > > the servers that are be powered-off of for several days. > > > > > > What I think is that the DNS cache entry expires > > > ( and I think that it is valid behaviour.) > > > > > > > > > Expriment that can be done: > > > > > > * Restart dnsmasq, so it forgets about dhcp-hosts in DNS cache > > > * Check cache dump with SIGUSR1 > > > * Power-on an infinite DHCP client e.g. the Linux VM > > > * Check cache dump with SIGUSR1 > > > * Regular work with the example Linux VM > > > * Power-off the infinite DHCP client > > > * Sample several days the cache dump > > > * Report when the DNS entry of the powered-off server is gone > > > > > > > Thanks! That makes sense. I will give that a shot. > > > Cool. I look forward on feedback. > > > > Groeten > Geert Stappers > -- > Silence is hard to parse > > _______________________________________________ > Dnsmasq-discuss mailing list > Dnsmasq-discuss@lists.thekelleys.org.uk > http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss >
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