centos7关闭不必要的服务和端口

云服务器开启很多不必要的端口，造成安全隐患

TCP

25端口：邮件服务

systemctl stop postfix

53端口 ：域名解析服务

systemctl stop rhel-domainname

111端口：SUN公司的RPC服务所有端口

systemctl stop rpcbind
systemctl stop rpcbind.socket
systemctl stop rpcbind.target

631端口：打印服务

systemctl stop cups

UDP

5353端口：多播DNS(multicastDNS)/DNS-SD网络服务

systemctl stop avahi-daemon
systemctl stop avahi-daemon.socket

查看端口命令:

grep 端口号 /etc/services|head

一键停止禁用:

ss -ntlp
systemctl stop rhel-domainname
systemctl stop cups
systemctl stop rpcbind
systemctl stop rpcbind.socket
systemctl stop rpcbind.target
systemctl stop dnsmasq
systemctl stop postfix
systemctl stop avahi-daemon
systemctl stop avahi-daemon.socket
ifconfig virbr0 down
brctl delbr virbr0

systemctl disable rpcbind
systemctl disable rpcbind.socket
systemctl disable rpcbind.target
systemctl disable cups
systemctl disable dnsmasq
systemctl disable rhel-domainname
systemctl disable postfix
systemctl disable avahi-daemon
systemctl disable avahi-daemon.socket
systemctl disable libvirtd
ss -ntlp 
exit