CentOS6.9优化

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/qq_28254093/article/details/81668213

#3.配置服务器ip名称解析
	\cp /etc/hosts{,.bak}
	cat >/etc/hosts<<EOF
	127.0.0.1 	localhost localhost.localdomain localhost4 localhost4.localdomain4
	::1			localhost localhost.localdomain localhost6 localhost6.localdomain
	EOF
#4.更改yum源
	mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
	mv /etc/yum.repos.d/epel.repo /etc/yum.repos.d/epel.repo.backup
	mv /etc/yum.repos.d/epel-testing.repo /etc/yum.repos.d/epel-testing.repo.backup
	
	wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
	wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-6.repo
	
#5.关闭selinux
	sed -i.bak 's/SELINUX-enforcing/SELINUX-disabled/' /etc/selinux/config
	grep  SELINUX-disabled /etc/selinux/config
	setenforce 0
	getenforce

#6.关闭 iptables
	/etc/init.d/iptables stop
	/etc/init.d/iptables stop
	chkconfig iptables off
#7.精简开机自启动服务
	export LANG-en
	chkconfig|egrep -v "crond|sshd|network|rsyslog|sysstat"|awk '{print "chkconfig",$1,"off"}'|bash
	chkconfig --list|grep 3:on
#8.提升oldboy可以sudo
	useradd oldboy
	echo 123456|passwd --stdin oldboy
	\cp /etc/sudoers /etc/sudoers.ori
	echo "oldboy ALL=(ALL) NOPASSWD:ALL " >> /etc/sudoers
	tail -l /etc/sudoers
	visudo -c
#9. 英文字符集
	cp /etc/sysconfig/i18n /etc/sysconfig/i18n.ori
	echo 'LANG="en_US.UTF-8"'  >/etc/sysconfig/i18n
	source /etc/sysconfig/i18n
	echo $LANG
#10.时间同步
	echo '#time sync by jpw at 2018-08-14' >> /var/spool/cron/root
	echo '*/5 * * * * /usr/sbin/ntpdate pool.ntp.org >/dev/null 2>&1' >> /var/spool/cron/root
	crontab -l
#11.命令行安全（可不设置）
	#echo 'export TMOUT=300' >>/etc/profile
	#echo 'export HISTSIZE=5' >>/etc/profile
	#echo 'export HISTFILESIZE=5' >>/etc/profile
	#tail -3 /etc/profile
	#. /etc/profile
#12.大文件描述
	echo '*                  -                         nofile        65535' >> /etc/security/limits.conf
	tail -1 /etc/security/limits.conf
	
#13.内核优化
	cat >> /etc/sysctl.conf<<EOF
	net.ipv4.tcp_fin_timeout = 2
	net.ipv4.tcp_tw_reuse = 1
	net.ipv4.tcp_tw_recycle = 1
	net.ipv4.tcp_syncookies = 1
	net.ipv4.tcp_keepalive_time = 600
	net.ipv4.ip_local_prot_range = 4000  65000
	net.ipv4.tcp_max_syn_backlog = 16384
	net.ipv4.tcp_max_tw_buckets = 36000
	net.ipv4.route.gc_timeout = 100
	net.ipv4.tcp_syn_retries = 1
	net.ipv4.tcp_synack_retries = 1
	net.core.somaxconn = 16384
	net.core.netdev_max_backlog =16384
	net.ipv4.tcp_max_orphans = 16384
	#以下参数参数是对防火墙的优化，防火墙不开会提示 ，可以忽略不理
	#net.nf_conntrack_max = 25000000 
	#net.netfilter.nf_conntrack_max = 25000000 
	#net.netfilter.nf_conntrack_tcp_timeout_established = 180
	#net.netfilter.nf_conntrack_tcp_timeout_time_wait = 120
	#net.netfilter.nf_conntrack_tcp_timeout_close_wait = 60
	#net.netfilter.nf_conntrack_tcp_timeout_fin_wait = 120
	EOF
	sysctl -p
#14.常用小软件
	yum install lrzsz nmap tree dos2unix nc telnet sl -y
#15.ssh连接速度慢优化
	sed -i.bak 's@#UseDNS yes@UseDNS no@g;s@^GSSAPIAuthentication yes@GSSAPIAuthentication no@g' /etc/ssh/sshd_config
	/etc/init.d/sshd reload