安装完centos7之后会遇到virbr0的虚拟网卡，该网卡存在会导致DNS服务器无法正常工作，下面介绍如何正确删除该网卡。
第一步：
[root@localhost ~]# ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:ca:2e:fc brd ff:ff:ff:ff:ff:ff inet 192.168.0.110/24 brd 192.168.0.255 scope global dynamic eno16777736 valid_lft 6769sec preferred_lft 6769sec inet6 fe80::20c:29ff:feca:2efc/64 scope link valid_lft forever preferred_lft forever 3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000 link/ether 52:54:00:d1:33:3a brd ff:ff:ff:ff:ff:ff inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0 valid_lft forever preferred_lft forever 4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 1000 link/ether 52:54:00:d1:33:3a brd ff:ff:ff:ff:ff:ff
第二步：
[root@localhost ~]# virsh net-destroy default 网络 default 被删除
第三步：
[root@localhost ~]# virsh net-undefine default 网络 default 已经被取消定义
第四步：
[root@localhost ~]# systemctl restart libvirtd.service
打完收工
原文：http://13042032.blog.51cto.com/13032032/1949028