


Problem:
The server cannot access the external network normally after restarting (because the server needs to pass the school network authentication).
Solution process:
First check whether the DNS and the like are normal
Then try to visit baidu.com After trying
, I found that I could not access baidu.com normally, so I judged whether campus network authentication had not yet been performed. I accessed the campus network authentication website (172.18.2.2) and found that I could not ping!
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So I started thinking (PS: Host IP: 172.18.72.18),
View routing information
The default route is 172.18.72.254
Access the gateway again and ping 172.18.72.254 and you can ping it
However, 172.18.2.2 cannot be pinged.
Logically speaking, this is a network unreachability situation that does not occur in the same network segment. However, when testing another 192.xxx host, it can access 172.18.2.2. . It shows that there is still a problem with the configuration.
First clear the current routing information (check the network card information, and then clear it):
After clearing, restart the network card:
Then check the configuration file of the network card (mine is eth0)
After the configuration is completed, execute the command There should be no problem with service network restart. Then perform arp verification (normal work)
Execute the command dhclient to access 172.18.2.2 again, and it works.
Note: This article only applies to offline machines. If the ssh object is an online machine, please operate with caution
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