為什麼啟用 ufw 後我無法 ping 通任何網域名稱/主機名稱？
[root@ip-172-31-23-37 ec2-user]# ping google.com
ping: google.com: Name or service not known
[root@ip-172-31-23-37 ec2-user]# ufw disable
Firewall stopped and disabled on system startup
[root@ip-172-31-23-37 ec2-user]# ping google.com
PING google.com (74.125.24.100) 56(84) bytes of data.
64 bytes from 74.125.24.100 (74.125.24.100): icmp_seq=1 ttl=100 time=2.14 ms
64 bytes from 74.125.24.100 (74.125.24.100): icmp_seq=2 ttl=100 time=2.19 ms
^C
--- google.com ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 2.149/2.170/2.192/0.051 ms
[root@ip-172-31-23-37 ec2-user]# ufw enable
Command may disrupt existing ssh connections. Proceed with operation (y|n)? y
Firewall is active and enabled on system startup
[root@ip-172-31-23-37 ec2-user]# ping google.com
ping: google.com: Name or service not known
除了使用命令定義之外，我禁用了所有傳出流量ufw default deny outgoing。 UFW狀態：
80 ALLOW OUT Anywhere
443 ALLOW OUT Anywhere
3306 ALLOW OUT Anywhere
2465 ALLOW OUT Anywhere
3306/tcp ALLOW OUT Anywhere
3306/udp ALLOW OUT Anywhere
127.0.0.1 3306 ALLOW OUT Anywhere
80 (v6) ALLOW OUT Anywhere (v6)
443 (v6) ALLOW OUT Anywhere (v6)
3306 (v6) ALLOW OUT Anywhere (v6)
2465 (v6) ALLOW OUT Anywhere (v6)
3306/tcp (v6) ALLOW OUT Anywhere (v6)
3306/udp (v6) ALLOW OUT Anywhere (v6)
我已經設定接受 icmp 到/etc/ufw/before.rules文件
# allow outbound icmp
-A ufw-before-output -p icmp -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT
-A ufw-before-output -p icmp -m state --state ESTABLISHED,RELATED -j ACCEPT
答案1
您尚未允許出站 DNS 流量，因此名稱無法解析為 IP 位址。