操作系统：Linux Mint 18.2 Cinnamon + Windows 10 Pro；双启动。
我刚刚使用过这个网站http://test-ipv6.com/检查我的 IPv6 准备情况。
Windows 10 专业版上的结果：
Linux Mint 18.2 Cinnamon 上的结果：
如你所见，我有一些我的 Linux Mint 上的 DNS 设置有问题。但一切似乎都已打开，例如在网络设置 - IPv6 部分：
我不确定在哪里查找失败的 DNS 设置。或者 Linux Mint 18 还没有为 IPv6 做好准备吗？
编辑1：
$ cat /etc/resolv.conf
nameserver 209.222.18.222
nameserver 209.222.18.218
但在网络管理器中，我将 Google DNS 视为主要 DNS，而我的 IPS 则视为次要 DNS，我已在路由器的 DHCP 中的 IPv4 部分中对其进行了配置：
我想我的笔记本电脑正在使用这些。
$ nmcli dev show | grep DNS
IP4.DNS[1]: 8.8.8.8
IP4.DNS[2]: 10.255.255.10
IP6.DNS[1]: 2a02:768:0:1010::3
IP6.DNS[2]: 2a02:768:0:1010::2
我承认我根本不懂IPv6，但我不明白为什么在Windows 上测试，因此IPv6 是完全可操作的，而在Linux 上却不行。
$ cat /etc/gai.conf
# Configuration for getaddrinfo(3).
#
# So far only configuration for the destination address sorting is needed.
# RFC 3484 governs the sorting. But the RFC also says that system
# administrators should be able to overwrite the defaults. This can be
# achieved here.
#
# All lines have an initial identifier specifying the option followed by
# up to two values. Information specified in this file replaces the
# default information. Complete absence of data of one kind causes the
# appropriate default information to be used. The supported commands include:
#
# reload <yes|no>
# If set to yes, each getaddrinfo(3) call will check whether this file
# changed and if necessary reload. This option should not really be
# used. There are possible runtime problems. The default is no.
#
# label <mask> <value>
# Add another rule to the RFC 3484 label table. See section 2.1 in
# RFC 3484. The default is:
#
#label ::1/128 0
#label ::/0 1
#label 2002::/16 2
#label ::/96 3
#label ::ffff:0:0/96 4
#label fec0::/10 5
#label fc00::/7 6
#label 2001:0::/32 7
#
# This default differs from the tables given in RFC 3484 by handling
# (now obsolete) site-local IPv6 addresses and Unique Local Addresses.
# The reason for this difference is that these addresses are never
# NATed while IPv4 site-local addresses most probably are. Given
# the precedence of IPv6 over IPv4 (see below) on machines having only
# site-local IPv4 and IPv6 addresses a lookup for a global address would
# see the IPv6 be preferred. The result is a long delay because the
# site-local IPv6 addresses cannot be used while the IPv4 address is
# (at least for the foreseeable future) NATed. We also treat Teredo
# tunnels special.
#
# precedence <mask> <value>
# Add another rule to the RFC 3484 precedence table. See section 2.1
# and 10.3 in RFC 3484. The default is:
#
#precedence ::1/128 50
#precedence ::/0 40
#precedence 2002::/16 30
#precedence ::/96 20
#precedence ::ffff:0:0/96 10
#
# For sites which prefer IPv4 connections change the last line to
#
precedence ::ffff:0:0/96 100
#
# scopev4 <mask> <value>
# Add another rule to the RFC 6724 scope table for IPv4 addresses.
# By default the scope IDs described in section 3.2 in RFC 6724 are
# used. Changing these defaults should hardly ever be necessary.
# The defaults are equivalent to:
#
#scopev4 ::ffff:169.254.0.0/112 2
#scopev4 ::ffff:127.0.0.0/104 2
#scopev4 ::ffff:0.0.0.0/96 14
所以，几乎所有内容都被注释掉了。
另外，您问我正在使用哪个 DHCP 客户端：
$ dhclient --help
Internet Systems Consortium DHCP Client 4.3.3
...
编辑2：
$ cat /etc/dhcp/dhclient.conf
# Configuration file for /sbin/dhclient.
#
# This is a sample configuration file for dhclient. See dhclient.conf's
# man page for more information about the syntax of this file
# and a more comprehensive list of the parameters understood by
# dhclient.
#
# Normally, if the DHCP server provides reasonable information and does
# not leave anything out (like the domain name, for example), then
# few changes must be made to this file, if any.
#
option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
send host-name = gethostname();
request subnet-mask, broadcast-address, time-offset, routers,
domain-name, domain-name-servers, domain-search, host-name,
dhcp6.name-servers, dhcp6.domain-search, dhcp6.fqdn, dhcp6.sntp-servers,
netbios-name-servers, netbios-scope, interface-mtu,
rfc3442-classless-static-routes, ntp-servers;
#send dhcp-client-identifier 1:0:a0:24:ab:fb:9c;
#send dhcp-lease-time 3600;
#supersede domain-name "fugue.com home.vix.com";
#prepend domain-name-servers 127.0.0.1;
#require subnet-mask, domain-name-servers;
timeout 300;
#retry 60;
#reboot 10;
#select-timeout 5;
#initial-interval 2;
#script "/sbin/dhclient-script";
#media "-link0 -link1 -link2", "link0 link1";
#reject 192.33.137.209;
#alias {
# interface "eth0";
# fixed-address 192.5.5.213;
# option subnet-mask 255.255.255.255;
#}
#lease {
# interface "eth0";
# fixed-address 192.33.137.200;
# medium "link0 link1";
# option host-name "andare.swiftmedia.com";
# option subnet-mask 255.255.255.0;
# option broadcast-address 192.33.137.255;
# option routers 192.33.137.250;
# option domain-name-servers 127.0.0.1;
# renew 2 2000/1/12 00:00:01;
# rebind 2 2000/1/12 00:00:01;
# expire 2 2000/1/12 00:00:01;
#}
编辑3：
将 IPv6 行复制粘贴到上面一行后：
cat /etc/dhcp/dhclient.conf
# Configuration file for /sbin/dhclient.
#
# This is a sample configuration file for dhclient. See dhclient.conf's
# man page for more information about the syntax of this file
# and a more comprehensive list of the parameters understood by
# dhclient.
#
# Normally, if the DHCP server provides reasonable information and does
# not leave anything out (like the domain name, for example), then
# few changes must be made to this file, if any.
#
option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
send host-name = gethostname();
request subnet-mask, broadcast-address, time-offset, routers,
dhcp6.name-servers, dhcp6.domain-search, dhcp6.fqdn, dhcp6.sntp-servers,
domain-name, domain-name-servers, domain-search, host-name,
netbios-name-servers, netbios-scope, interface-mtu,
rfc3442-classless-static-routes, ntp-servers;
#send dhcp-client-identifier 1:0:a0:24:ab:fb:9c;
#send dhcp-lease-time 3600;
#supersede domain-name "fugue.com home.vix.com";
#prepend domain-name-servers 127.0.0.1;
#require subnet-mask, domain-name-servers;
timeout 300;
#retry 60;
#reboot 10;
#select-timeout 5;
#initial-interval 2;
#script "/sbin/dhclient-script";
#media "-link0 -link1 -link2", "link0 link1";
#reject 192.33.137.209;
#alias {
# interface "eth0";
# fixed-address 192.5.5.213;
# option subnet-mask 255.255.255.255;
#}
#lease {
# interface "eth0";
# fixed-address 192.33.137.200;
# medium "link0 link1";
# option host-name "andare.swiftmedia.com";
# option subnet-mask 255.255.255.0;
# option broadcast-address 192.33.137.255;
# option routers 192.33.137.250;
# option domain-name-servers 127.0.0.1;
# renew 2 2000/1/12 00:00:01;
# rebind 2 2000/1/12 00:00:01;
# expire 2 2000/1/12 00:00:01;
#}
编辑4：
也许是我的 VPN 提供商应用程序造成的，我没有做任何更改。我目前没有使用 VPN，所以我想测试我的 Linux 是否支持 IPv6。 resolv.conf 中的名称服务器属于 VPN 提供商：Private Internet Access。
试图找出为什么resolv.conf不更新：
$ lsattr /etc/resolv.conf
-------------e-- /etc/resolv.conf
编辑5：
$ sudo tcpdump -i eth0 udp port 53
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
13:28:35.416720 IP 192.168.0.11.46858 > resolver1.privateinternetaccess.com.domain: 22927+ A? imap.gmail.com. (32)
13:28:35.416730 IP 192.168.0.11.46858 > resolver1.privateinternetaccess.com.domain: 8909+ AAAA? imap.gmail.com. (32)
13:28:35.416974 IP 192.168.0.11.39732 > resolver1.privateinternetaccess.com.domain: 35471+ PTR? 222.18.222.209.in-addr.arpa. (45)
13:28:35.436305 IP 192.168.0.11.52326 > resolver1.privateinternetaccess.com.domain: 65414+ A? live.mozillamessaging.com. (43)
13:28:35.436310 IP 192.168.0.11.52326 > resolver1.privateinternetaccess.com.domain: 30886+ AAAA? live.mozillamessaging.com. (43)
13:28:35.478049 IP 192.168.0.11.46175 > resolver1.privateinternetaccess.com.domain: 5292+ A? mx.endora.cz. (30)
13:28:35.478053 IP 192.168.0.11.46175 > resolver1.privateinternetaccess.com.domain: 16624+ AAAA? mx.endora.cz. (30)
13:28:35.815497 IP 192.168.0.11.50734 > resolver1.privateinternetaccess.com.domain: 17117+ A? clients1.google.com. (37)
13:28:35.815508 IP 192.168.0.11.50734 > resolver1.privateinternetaccess.com.domain: 34551+ AAAA? clients1.google.com. (37)
13:28:35.816481 IP resolver1.privateinternetaccess.com.domain > 192.168.0.11.46175: 5292 1/0/0 A 88.86.120.212 (46)
13:28:35.818739 IP resolver1.privateinternetaccess.com.domain > 192.168.0.11.46175: 16624 0/1/0 (86)
13:28:35.959874 IP resolver1.privateinternetaccess.com.domain > 192.168.0.11.50734: 17117 2/0/0 CNAME clients.l.google.com., A 172.217.12.142 (77)
13:28:35.959899 IP resolver1.privateinternetaccess.com.domain > 192.168.0.11.50734: 34551 2/0/0 CNAME clients.l.google.com., AAAA 2607:f8b0:4006:819::200e (89)
13:28:35.972396 IP 192.168.0.11.50409 > resolver1.privateinternetaccess.com.domain: 53313+ A? ocsp2.globalsign.com. (38)
13:28:35.972406 IP 192.168.0.11.50409 > resolver1.privateinternetaccess.com.domain: 62184+ AAAA? ocsp2.globalsign.com. (38)
13:28:36.145921 IP resolver1.privateinternetaccess.com.domain > 192.168.0.11.50409: 62184 3/0/0 CNAME cdn.globalsigncdn.com., AAAA 2400:cb00:2048:1::681f:4a7c, AAAA 2400:cb00:2048:1::681f:4b7c (126)
13:28:36.153394 IP resolver1.privateinternetaccess.com.domain > 192.168.0.11.50409: 53313 3/0/0 CNAME cdn.globalsigncdn.com., A 104.31.75.124, A 104.31.74.124 (102)
13:28:36.345446 IP 192.168.0.11.39036 > resolver1.privateinternetaccess.com.domain: 49155+ A? www.googleapis.com. (36)
13:28:36.345462 IP 192.168.0.11.39036 > resolver1.privateinternetaccess.com.domain: 10791+ AAAA? www.googleapis.com. (36)
13:28:36.483314 IP resolver1.privateinternetaccess.com.domain > 192.168.0.11.39036: 49155 13/0/0 CNAME googleapis.l.google.com., A 172.217.6.234, A 172.217.10.234, A 172.217.12.170, A 172.217.12.202, A 172.217.9.234, A 172.217.10.10, A 172.217.10.42, A 172.217.10.74, A 172.217.10.138, A 172.217.3.106, A 172.217.12.138, A 172.217.6.202 (262)
13:28:36.483344 IP resolver1.privateinternetaccess.com.domain > 192.168.0.11.39036: 10791 2/0/0 CNAME googleapis.l.google.com., AAAA 2607:f8b0:4006:812::200a (98)
^C
编辑6：
sudo dhclient -r
sudo dhclient -v eth0
Internet Systems Consortium DHCP Client 4.3.3
Copyright 2004-2015 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Listening on LPF/eth0/d8:50:e6:05:e1:db
Sending on LPF/eth0/d8:50:e6:05:e1:db
Sending on Socket/fallback
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3 (xid=0x3ede007c)
DHCPREQUEST of 192.168.0.11 on eth0 to 255.255.255.255 port 67 (xid=0x7c00de3e)
DHCPOFFER of 192.168.0.11 from 192.168.0.1
DHCPACK of 192.168.0.11 from 192.168.0.1
/etc/resolvconf/update.d/libc: Warning: /etc/resolv.conf is not a symbolic link to /run/resolvconf/resolv.conf
bound to 192.168.0.11 -- renewal in 2147483648 seconds.
编辑7：
$ sudo tcpdump -i eth0 -vvv -n port 68
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
14:30:18.135530 IP (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from d8:50:e6:05:e1:db, length 300, xid 0x7a30842b, Flags [none] (0x0000)
Client-Ethernet-Address d8:50:e6:05:e1:db
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Request
Requested-IP Option 50, length 4: 192.168.0.11
Hostname Option 12, length 10: "vb-nb-mint"
Parameter-Request Option 55, length 18:
Subnet-Mask, BR, Time-Zone, Default-Gateway
Domain-Name, Domain-Name-Server, Option 119, Hostname
Netbios-Name-Server, Netbios-Scope, MTU, Classless-Static-Route
NTP, Classless-Static-Route, Classless-Static-Route-Microsoft, Static-Route
Option 252, NTP
END Option 255, length 0
PAD Option 0, length 0, occurs 18
14:30:18.136280 IP (tos 0x0, ttl 64, id 15220, offset 0, flags [none], proto UDP (17), length 576)
192.168.0.1.67 > 192.168.0.11.68: [udp sum ok] BOOTP/DHCP, Reply, length 548, xid 0x7a30842b, Flags [none] (0x0000)
Your-IP 192.168.0.11
Client-Ethernet-Address d8:50:e6:05:e1:db
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: ACK
Server-ID Option 54, length 4: 192.168.0.1
Lease-Time Option 51, length 4: 4294967295
Subnet-Mask Option 1, length 4: 255.255.255.0
Default-Gateway Option 3, length 4: 192.168.0.1
Domain-Name-Server Option 6, length 8: 8.8.8.8,10.255.255.10
END Option 255, length 0
PAD Option 0, length 0, occurs 270
^C
+
$ cat /run/resolvconf/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 8.8.8.8
nameserver 10.255.255.10
nameserver 127.0.1.1
答案1
在 /etc/gai.conf 中，您需要注释掉 IPv6 优先于 IPv4 的行，如下所示：
# precedence ::ffff:0:0/96 100
您还需要编辑 /etc/dhclient/dhclient6.conf，如果这还不够，则可以将 -6 参数传递给 dhclient。
我还建议更正 resolv.conf 链接。
我还可以发誓 dhclient 只使用通过 DHCP 传递的前两个 DNS 服务器，但我可能是错的。
编辑：
上面的步骤是正确的，即我们第一步注释掉该行：
precedence ::ffff:0:0/96 100在以下文件中：
/etc/gai.conf执行提到的步骤在微软文档中适用于基于Ubuntu 16.04的Linux Mint 18.x：
创建以下文件：
/etc/dhcp/dhclient6.conf内容：
timeout 10;创建以下文件：
/etc/network/interfaces.d/50-cloud-init.cfg内容：
iface eth0 inet6 auto up sleep 5 up dhclient -1 -6 -cf /etc/dhcp/dhclient6.conf -lf /var/lib/dhcp/dhclient6.eth0.leases -v eth0 || true最后创建符号链接，同时覆盖原始链接
resolv.conf：ln -sf /run/resolvconf/resolv.conf /etc/resolv.conf重新启动，瞧，来自 DHCP 的 IPv6 正在工作。
答案2
您可以在 /etc/gai.conf 文件中添加该行precedence 2001:470::/32 100并注释，使 IPv6 优先于 IPv4precedence ::ffff:0:0/96 100