标签：root etc host DNS Linux test NetworkManager yes my
系统重启后/etc/resolv.conf 被重置
1 [root@my-test-host ~]# cat /etc/resolv.conf 2 # Generated by NetworkManager
当前网卡配置文件
1 [root@my-test-host ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0 2 3 # Created by cloud-init on instance boot automatically, do not edit. 4 # 5 DEVICE=eth0 6 HWADDR=FA:16:3E:C1:B6:67 7 MTU=1450 8 ONBOOT=yes 9 TYPE=Ethernet 10 USERCTL=no 11 IPADDR=10.200.5.164 12 PREFIX=24 13 GATEWAY=10.200.5.1 14 IPV6INIT=yes 15 IPV6ADDR=2409:8c60:2500:28::405:5a4/112 16 IPV6_DEFAULTGW=2409:8c60:2500:28::405:1 17 PROXY_METHOD=none 18 BROWSER_ONLY=no 19 DEFROUTE=yes 20 IPV4_FAILURE_FATAL=no 21 IPV6_AUTOCONF=yes 22 IPV6_DEFROUTE=yes 23 IPV6_FAILURE_FATAL=no 24 NAME="System eth0" 25 UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03 26 BOOTPROTO=none
使用nmcli添加DNS服务器
[root@my-test-host ~]# nmcli c modify "System eth0" ipv4.dns "10.200.5.4 10.200.6.4"
nmcli添加DNS后/etc/resolv.conf 中并没有相应的配置生成。此时也不能完成域名解析，也就是说虽然通过nmcli已经添加DNS server但系统最终还是会去/etc/resolv.conf查询dns server配置。
1 [root@my-test-host ~]# cat /etc/resolv.conf 2 # Generated by NetworkManager 3 [root@my-test-host ~]# nmcli c s "System eth0" |grep dns 4 connection.mdns: -1 (default) 5 ipv4.dns: 10.200.5.4,10.200.6.4 6 ipv4.dns-search: -- 7 ipv4.dns-options: -- 8 ipv4.dns-priority: 0 9 ipv4.ignore-auto-dns: no 10 ipv6.dns: -- 11 ipv6.dns-search: -- 12 ipv6.dns-options: -- 13 ipv6.dns-priority: 0 14 ipv6.ignore-auto-dns: no 15 [root@my-test-host ~]# ping www.baidu.com 16 ping: www.baidu.com: Name or service not known
查看网卡配置，多出的两条DNS配置是通过nmcli添加DNS时自动更新的。
1 [root@my-test-host ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0 2 # Created by cloud-init on instance boot automatically, do not edit. 3 # 4 DEVICE=eth0 5 HWADDR=FA:16:3E:C1:B6:67 6 MTU=1450 7 ONBOOT=yes 8 TYPE=Ethernet 9 USERCTL=no 10 IPADDR=10.200.5.164 11 PREFIX=24 12 GATEWAY=10.200.5.1 13 IPV6INIT=yes 14 IPV6ADDR=2409:8c60:2500:28::405:5a4/112 15 IPV6_DEFAULTGW=2409:8c60:2500:28::405:1 16 PROXY_METHOD=none 17 BROWSER_ONLY=no 18 DEFROUTE=yes 19 IPV4_FAILURE_FATAL=no 20 IPV6_AUTOCONF=yes 21 IPV6_DEFROUTE=yes 22 IPV6_FAILURE_FATAL=no 23 NAME="System eth0" 24 UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03 25 BOOTPROTO=none 26 DNS1=10.200.5.4 27 DNS2=10.200.6.4
尝试reload/load网卡配置，还是无法进行域名解析
[root@my-test-host ~]# nmcli c reload /etc/sysconfig/network-scripts/ifcfg-eth0 [root@my-test-host ~]# cat /etc/resolv.conf # Generated by NetworkManager [root@my-test-host ~]# ping www.baidu.com ping: www.baidu.com: Name or service not known [root@my-test-host ~]# nmcli c load /etc/sysconfig/network-scripts/ifcfg-eth0 [root@my-test-host ~]# ping www.baidu.com ping: www.baidu.com: Name or service not known
重启NetworkManager 后/etc/resolv.conf 自动更新了DNS server
1 [root@my-test-host ~]# systemctl restart NetworkManager 2 [root@my-test-host ~]# cat /etc/resolv.conf 3 # Generated by NetworkManager 4 nameserver 10.200.5.4 5 nameserver 10.200.6.4
通过命令nmcli清除DNS并重启NetworkManager，发现/etc/resolv.conf 中之前添加的nameserver并没有被清理，但ifcfg-eth0中的配置被清理了。也就是说重启NetworkManager会增加/etc/resolv.conf中的配置，但似乎不会删除已有配置。当然reboot后/etc/resolv.conf还是会被重置的。
1 [root@my-test-host ~]# nmcli c modify "System eth0" ipv4.dns "" 2 [root@my-test-host ~]# systemctl restart NetworkManager 3 [root@my-test-host ~]# cat /etc/resolv.conf 4 # Generated by NetworkManager 5 nameserver 10.200.5.4 6 nameserver 10.200.6.4 7 [root@my-test-host ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0 8 # Created by cloud-init on instance boot automatically, do not edit. 9 # 10 DEVICE=eth0 11 HWADDR=FA:16:3E:C1:B6:67 12 MTU=1450 13 ONBOOT=yes 14 TYPE=Ethernet 15 USERCTL=no 16 IPADDR=10.200.5.164 17 PREFIX=24 18 GATEWAY=10.200.5.1 19 IPV6INIT=yes 20 IPV6ADDR=2409:8c60:2500:28::405:5a4/112 21 IPV6_DEFAULTGW=2409:8c60:2500:28::405:1 22 PROXY_METHOD=none 23 BROWSER_ONLY=no 24 DEFROUTE=yes 25 IPV4_FAILURE_FATAL=no 26 IPV6_AUTOCONF=yes 27 IPV6_DEFROUTE=yes 28 IPV6_FAILURE_FATAL=no 29 NAME="System eth0" 30 UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03 31 BOOTPROTO=none 32 [root@my-test-host ~]#
再测试下发现，当通过nmcli清空DNS时，重启NetworkManager服务/etc/resolv.conf 不会被重置，但通过nmcli改变了原来DNS配置（也就是ifcfg-eth0中的配置），重启NetworkManage是会更新/etc/resolv.conf的。
1 [root@my-test-host ~]# nmcli c modify "System eth0" ipv4.dns "8.8.8.8" 2 [root@my-test-host ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0 3 # Created by cloud-init on instance boot automatically, do not edit. 4 # 5 DEVICE=eth0 6 HWADDR=FA:16:3E:C1:B6:67 7 MTU=1450 8 ONBOOT=yes 9 TYPE=Ethernet 10 USERCTL=no 11 IPADDR=10.198.5.164 12 PREFIX=24 13 GATEWAY=10.198.5.1 14 IPV6INIT=yes 15 IPV6ADDR=2409:8c60:2500:28::405:5a4/112 16 IPV6_DEFAULTGW=2409:8c60:2500:28::405:1 17 PROXY_METHOD=none 18 BROWSER_ONLY=no 19 DEFROUTE=yes 20 IPV4_FAILURE_FATAL=no 21 IPV6_AUTOCONF=yes 22 IPV6_DEFROUTE=yes 23 IPV6_FAILURE_FATAL=no 24 NAME="System eth0" 25 UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03 26 BOOTPROTO=none 27 DNS1=8.8.8.8 28 [root@my-test-host ~]# cat /etc/resolv.conf 29 # Generated by NetworkManager 30 nameserver 10.198.5.4 31 nameserver 10.198.6.4 32 [root@my-test-host ~]# systemctl restart NetworkManager 33 [root@my-test-host ~]# cat /etc/resolv.conf 34 # Generated by NetworkManager 35 nameserver 8.8.8.8 36 [root@my-test-host ~]# sed -i '/DNS1/d' /etc/sysconfig/network-scripts/ifcfg-eth0 37 [root@my-test-host ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0 38 # Created by cloud-init on instance boot automatically, do not edit. 39 # 40 DEVICE=eth0 41 HWADDR=FA:16:3E:C1:B6:67 42 MTU=1450 43 ONBOOT=yes 44 TYPE=Ethernet 45 USERCTL=no 46 IPADDR=10.198.5.164 47 PREFIX=24 48 GATEWAY=10.198.5.1 49 IPV6INIT=yes 50 IPV6ADDR=2409:8c60:2500:28::405:5a4/112 51 IPV6_DEFAULTGW=2409:8c60:2500:28::405:1 52 PROXY_METHOD=none 53 BROWSER_ONLY=no 54 DEFROUTE=yes 55 IPV4_FAILURE_FATAL=no 56 IPV6_AUTOCONF=yes 57 IPV6_DEFROUTE=yes 58 IPV6_FAILURE_FATAL=no 59 NAME="System eth0" 60 UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03 61 BOOTPROTO=none 62 [root@my-test-host ~]# systemctl restart NetworkManager 63 [root@my-test-host ~]# cat /etc/resolv.conf 64 # Generated by NetworkManager 65 nameserver 8.8.8.8 66 [root@my-test-host ~]#
标签：root,etc,host,DNS,Linux,test,NetworkManager,yes,my 来源： https://www.cnblogs.com/myss/p/14220416.html
本站声明： 1. iCode9 技术分享网（下文简称本站）提供的所有内容，仅供技术学习、探讨和分享； 2. 关于本站的所有留言、评论、转载及引用，纯属内容发起人的个人观点，与本站观点和立场无关； 3. 关于本站的所有言论和文字，纯属内容发起人的个人观点，与本站观点和立场无关； 4. 本站文章均是网友提供，不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属；如您发现该文章侵犯了您的权益，可联系我们第一时间进行删除； 5. 本站为非盈利性的个人网站，所有内容不会用来进行牟利，也不会利用任何形式的广告来间接获益，纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。