centos7作为web服务器优化

1、关闭firewalld： 
systemctl stop firewalld.service #停止firewall
systemctl disable firewalld.service #禁止firewall开机启动
2、安装iptables防火墙 
yum install iptables-services #安装
iptables -nvL #查看信息
3、加大打开文件数的限制（open files） 
查看 
ulimit -n
ulimit -a
vi /etc/security/limits.conf
最后添加 
* soft nofile 1024000 
* hard nofile 1024000 
hive   – nofile 1024000 
hive   – nproc  1024000 

用户进程限制 
vi /etc/security/limits.d/20-nproc.conf
#加大普通用户限制 也可以改为unlimited
* soft nproc 40960
root soft nproc unlimited

此步骤需要重启机器生效，可以设置完后再重启 
4、网络线程优化 
vi /etc/sysctl.conf

加入下面几行 
# Disable IPv6
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
# Determines how often to check for stale neighbor entries.
net.ipv4.neigh.default.gc_stale_time=120
# Using arp_announce/arp_ignore to solve the ARP Problem
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.all.arp_announce=2
vm.swappiness = 0
net.ipv4.tcp_max_tw_buckets = 5000
net.ipv4.tcp_max_syn_backlog = 1024
net.ipv4.tcp_synack_retries = 2
net.ipv4.conf.lo.arp_announce=2
net.ipv4.tcp_keepalive_time = 1800
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_keepalive_intvl = 15
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_fin_timeout = 30
执行下面命令生效
/sbin/sysctl -p

5.时间校对 
cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
ntpdate us.pool.ntp.org
crontab -e
0-59/10 * * * * /usr/sbin/ntpdate us.pool.ntp.org | logger -t NTP
service crond restart

6.关闭root登录并修改ssh端口 
添加普通用户 
groupadd test
useradd -d /home/www/ -g test test1
passwd test1
iptables 开启6666端口  此步骤须先于下面步骤，否则会造成ssh连不上的 
vi /etc/sysconfig/iptables
添加 
-A INPUT -p tcp -m state –state NEW -m tcp –dport 6666 -j ACCEPT

修改ssh端口 
vi /etc/ssh/sshd_config 
找到#Port 22一段，这里是标识默认使用22端口，修改为如下： 
#Port 22 
Port 6666 

关闭root登录权限 
把
PermitRootLogin yes
改为
PermitRootLogin no

保存退出 

测试新用户能正常登录后方可以在iptables 禁用22端口了 
7.禁止开启ping 
禁止
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all
开启
echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all
#永久保存
vi /etc/rc.d/rc.local
echo 1 >/proc/sys/net/ipv4/icmp_echo_ignore_all
8.网络命令ifconfig 
bash: ifconfig: 未找到命令
yum -y install net-tools