Vmware虚机192.168.137.100访问外网域名www.baidu.com不通（常州企业内网-电信DNS61.177.7.1）
i.故障1：/etc/sysconfig/network-scripts/ifcfg-ens33的DNS配置错误
[root@localhost ~]# vim /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE="Ethernet"
BOOTPROTO="static"
DEFROUTE="yes"
IPV4_FAILURE_FATAL="no"
IPADDR=192.168.137.100
NETMASK=255.255.255.0
GATEWAY=192.168.137.254
DNS1=114.114.114.114
NAME="ens33"
UUID="0048fac2-be26-47bd-810a-024787942838"
DEVICE="ens33"
ONBOOT="yes"
<etc/sysconfig/network-scripts/ifcfg-ens33" 19L, 402C written
[root@localhost ~]# systemctl restart network
[root@localhost ~]# ping www.baidu.com
PING www.a.shifen.com (112.80.248.75) 56(84) bytes of data.
64 bytes from 112.80.248.75 (112.80.248.75): icmp_seq=1 ttl=128 time=10.9 ms
64 bytes from 112.80.248.75 (112.80.248.75): icmp_seq=2 ttl=128 time=8.45 ms
64 bytes from 112.80.248.75 (112.80.248.75): icmp_seq=3 ttl=128 time=9.14 ms
ii.故障2：问题原因：电信内部路由不通，形成路由环路
[root@localhost ~]# ping 61.177.7.1
PING 61.177.7.1 (61.177.7.1) 56(84) bytes of data.
From 202.97.92.21 icmp_seq=1 Time to live exceeded
From 202.97.92.21 icmp_seq=2 Time to live exceeded
From 202.97.92.21 icmp_seq=3 Time to live exceeded
C:\Users\GKHOS>tracert 61.177.7.1
通过最多 30 个跃点跟踪
到 c.center-dns.jsinfo.net [61.177.7.1] 的路由:
1 3 ms 1 ms 2 ms bogon [10.50.81.1]
2 1 ms 1 ms 2 ms bogon [192.168.102.1]
3 * * * 请求超时。
4 * * * 请求超时。
5 * * * 请求超时。
6 15 ms 16 ms 21 ms 58.216.44.101
7 24 ms 17 ms 20 ms 202.97.92.21
8 26 ms 17 ms 20 ms 202.97.92.22
9 27 ms 27 ms 21 ms 202.97.92.21
10 18 ms 19 ms 16 ms 202.97.92.22
11 22 ms 22 ms 33 ms 202.97.92.21
12 30 ms 27 ms 26 ms 202.97.92.22
13 27 ms 27 ms 31 ms 202.97.92.21