Bug 186806 - dhclient(8): cannot prepend ipv6 servers
Summary: dhclient(8): cannot prepend ipv6 servers
Status: Open
Alias: None
Product: Base System
Classification: Unclassified
Component: bin (show other bugs)
Version: 9.2-RELEASE
Hardware: Any Any
: Normal Affects Some People
Assignee: freebsd-bugs (Nobody)
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2014-02-16 01:30 UTC by Tom Pusateri
Modified: 2020-07-26 10:50 UTC (History)
3 users (show)

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Description Tom Pusateri 2014-02-16 01:30:00 UTC 
Google provides public IPv6 name servers. If you try to prepend them in
the dhclient.conf, you get an error because it won't accept IPv6 addresses.

interface "em0"
{
    prepend domain-name-servers 2001:4860:4860::8888, 2001:4860:4860::8844;
}

# /etc/rc.d/dhclient restart em0
Stopping dhclient.
Starting dhclient.
value 2001 exceeds max (255) for precision.
/etc/dhclient.conf line 13: too few numbers.
    prepend domain-name-servers 2001:
                                     ^
DHCPREQUEST on em0 to 255.255.255.255 port 67
DHCPACK from 172.16.21.1
bound to 172.16.21.107 -- renewal in 21600 seconds.


This doesn't work either:

interface "em0"
{
    prepend dhcp6.name-servers 2001:4860:4860::8888;
}

# /etc/rc.d/dhclient restart em0
Stopping dhclient.
Starting dhclient.
/etc/dhclient.conf line 14: no vendor named dhcp6.
    prepend dhcp6.name-servers 
                  ^
DHCPREQUEST on em0 to 255.255.255.255 port 67
DHCPACK from 172.16.21.1
bound to 172.16.21.107 -- renewal in 21600 seconds.

How-To-Repeat: configure /etc/dhclient.conf like above and restart dhclient.
Comment 1 Lars Engels freebsd_committer freebsd_triage 2014-10-07 20:13:20 UTC 
Still true on a recent HEAD.
Comment 2 Andrey V. Elsukov freebsd_committer freebsd_triage 2014-10-08 22:57:01 UTC 
dhclient(8) supports only DHCP protocol, for DCHPv6 you should use some another software.
Comment 3 Eitan Adler freebsd_committer freebsd_triage 2018-05-20 23:52:53 UTC 
For bugs matching the following conditions:
- Status == In Progress
- Assignee == "bugs@FreeBSD.org"
- Last Modified Year <= 2017

Do
- Set Status to "Open"
Comment 4 roy 2020-07-26 10:50:27 UTC 
FreeBSD ships with a resolvconf(8) implementation which dhclient should support.

So you can use that functionality to achieve the same results.
Try this in /etc/resolvconf.conf

name_servers="2001:4860:4860::8888, 2001:4860:4860::8844"