我有一台运行 UFW 的 Debian 9 服务器，我想阻止除端口 2122 (SSH) 和 80/443（对于 HTTP(s)）之外的所有传入请求。
我运行了以下命令：
ufw reset
ufw default deny incoming
ufw default allow outgoing
ufw allow incoming 2122/tcp
ufw allow 80/tcp
ufw allow 443/tcp
ufw enable
编译为：
ufw status verbose
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing), deny (routed)
New profiles: skip
To Action From
-- ------ ----
2122/tcp ALLOW IN Anywhere
80/tcp ALLOW IN Anywhere
443/tcp ALLOW IN Anywhere
2122/tcp (v6) ALLOW IN Anywhere (v6)
80/tcp (v6) ALLOW …