[systemd-devel] systemd-resolved cannot survive router reinstall

Thomas Suckow thomas.suckow at pnnl.gov
Thu Aug 21 08:50:18 PDT 2014

>> So the problem is not in networkd, sorry for the noise. The problem is
>> in OpenWRT that uses dnsmasq and stores dhcp lease information on
>> tmpfs. If I reboot the router it looses all the leases and machines
>> should update the information somehow. This is a problem for machines
>> in a separate network segment. I can not believe that OpenWRT
>> developers never tested such configuration. I am going to contact
>> openwrt/dnsmasq maillist and ask what is the right way to solve the
>> issue.

I suspect they know about this but are not concerned. Many DHCP servers
(I believe OpenWRT does as well) performs an arp check before giving out
an ip address. Thus, even if they loose the lease table, IP conflicts
should be impossible.

>> PS According to off-list discussion with Tom FORCERENEW dhcp option
>> http://tools.ietf.org/html/rfc3203 is what suppose to fix this issue.
>> But dnsmasq does not support it.

This seems like a nice extension, OpenWRT would probably be open to this.
I suspect this would get implemented such that if the DHCP server detects
an unknown IP in its lease range it sends FORCERENEW to it.


More information about the systemd-devel mailing list