dhcpcd sending OPTION_CLIENT_FQDN with DHCPv6 message type Information-request

[ustaerk]

Hi all,

while debugging some weird issues with IPv6 name reolution with my home router, I stumbled upon the following and wanted to check with you whether this is a bug or a simple configuration issue.

I dumped the traffic on my ethernet interface during DHCPv6 lookup and found the following in Wireshark:

Reading the relevant RFC4704 it clearly states:

A client MUST only include the Client FQDN option in SOLICIT, REQUEST, RENEW, or REBIND messages.

What I am seeing though is dhcpcd sending an Information-request message with the Client FQDN option set.

Here is me dhcpcd.conf which I believe to be correct (vannilla Raspbian, comments ommited):

hostname
clientid
persistent
option rapid_commit
option domain_name_servers, domain_name, domain_search, host_name
option classless_static_routes
option interface_mtu
require dhcp_server_identifier
slaac private

I am running dhcpcd 8.1.2 on Raspbian Buster:

pi@berry:~ $ dhcpcd --version
dhcpcd 8.1.2
Copyright (c) 2006-2019 Roy Marples
Compiled in features: INET ARP ARPing IPv4LL INET6 DHCPv6 AUTH
pi@berry:~ $ uname -a
Linux berry 5.10.17-v7l+ #1421 SMP Thu May 27 14:00:13 BST 2021 armv7l GNU/Linux
pi@berry:~ $ lsb_release -a
No LSB modules are available.
Distributor ID: Raspbian
Description:    Raspbian GNU/Linux 10 (buster)
Release:        10
Codename:       buster
pi@berry:~ $ dpkg -l|grep dhcpcd
ii  dhcpcd5                              1:8.1.2-1+rpt1                          armhf        DHCPv4, IPv6RA and DHCPv6 client with IPv4LL support