Bug 260353

Summary: net/dual-dhclient: incapable of resolving IPv4 DHCP response correctly
Product: Ports & Packages Reporter: O. Hartmann <ohartmann>
Component: Individual Port(s)Assignee: Colin Percival <cperciva>
Status: New ---    
Severity: Affects Many People Flags: bugzilla: maintainer-feedback? (cperciva)
Priority: ---    
Version: Latest   
Hardware: Any   
OS: Any   

Description O. Hartmann 2021-12-12 10:10:24 UTC 
On notebooks running 13-STABLE within a dual stack network, we use the port net/dual-dhclient.

In /etc/rc.conf the replacement according to instructions on how to use net/dual-dhclient has been made according to:

[...]
#dhclient_program="/sbin/dhclient"  # Path to dhcp client program.
dhclient_program="/usr/local/sbin/dual-dhclient"
dhclient_flags=""   # Extra flags to pass to dhcp client.

This doesn't work as expected. In almost every scenario, network we hooked up to and every network config, this port misses the IPv4 offers of the DHCP server when it comes to DNS.
/etc/resolv.conf then only contains the line "nameserver "IPv6-address" - noting more. The DHCP's domain or search offering and in 9 of 10 cases the IPv4 nameservice is missing. 
The IPv4 itself is properly received and applied to the appropriate NIC - same with IPv6.
Comment 1 Colin Percival freebsd_committer freebsd_triage 2021-12-12 15:21:32 UTC 
Sounds like the two dhclients are fighting over resolv.conf.  You should be able to fix this using resolvconf.conf?
Comment 2 Colin Percival freebsd_committer freebsd_triage 2021-12-12 15:22:31 UTC 
BTW, I don't use dual-dhclient any more -- I was convinced to switch over to using rtsold and having that spawn the v6 dhclient.  But I think either way you would have the same resolv.conf issue.