[Dnsmasq-discuss] clients of DHCPv6 with constructed IPv6 address range are not notified on address range change

[Andrey Vakhitov]

Thanks for a great dnsmasq software.

 

I'm using dnsmasq 2.79 in combination with IPv6 prefix delegation. The
prefixes are changing daily due to daily reconnect of upstream router.
Dhcpcd is used to handle prefix delegation on external interface and apply
new address to internal interface (dmz0). Dnsmasq picks up the prefix
assigned to the internal interface by dhcpcd and server RA and DHCPv6
server.

 

dhcp-range=set:dmz6,::,constructor:dmz0,ra-stateless,ra-names

dhcp-host=id:00:02:00:00:ab:11:9b:74:21:c0:e9:5d:1c:18,set:dmzfix6,[::56],dm
zhost

 

Initially the host gets IPv6 address via DHCPv6 correctly, DNS resolution
works as expected, everything seems to be ok. But after reconnect (and
according prefix change) the client stays with the IPv6 address from old
prefix and doesn't update it. I've used tcpdump to monitor DHCP-related
traffic and could not see DHCPv6 RECONFIGURE message sent by dnsmasq to
clients on prefix change. I assume that this is the cause of the problem:
DHCP clients are not aware of changed prefix and can't act without
corresponding notification from server.

As dhcp client I use build-in DHCP client from system-networkd, just for
info, maybe it matters.

 

If I'm wrong with my assumption I'd appreciate any explanation helping me to
configure dnsmasq and DHCP client properly.

 

Best regards,

--

Andrey Vakhitov

 

E-Mail:   <mailto:andrei at vakhitov.net> andrey at vakhitov.net
Stuttgart, Germany

 

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