优化内容：（1.设置history历史记录（2.添加普通用户，设置sudo权限（3.关闭selinux（4.配置iptables（5.禁止root远程用户登录（6.修改远程端口（7.精简开机启动服务器（8.修改最大连接数 ulimit（9.禁止使用Ctrl+Alt+Del快捷键重启服务器（10.修改默认DNS（11.优化内核参数 [根据实际情况调整]-------------------------------------------------------------------------------------------优化内容：（1.设置history历史记录#/bin/bash Date=`date -d now +%Y%m%d%H%M%S`#echo $Datecp /etc/profile /etc/profile_$Date echo -ne "HISTFILESIZE=2000HISTSIZE=2000export HISTTIMEFORMAT=\"%Y%m%d-%H%M%S:\"export PROMPT_COMMAND='{ command=\$(history 1 | { read x y; echo \$y; } | cut -d \":\" -f2-);logger -p local1.notice -t bash \"(user=\$USER,ppid=\$PPID,from=\$SSH_CLIENT,pwd=\$PWD,ssh_tty=\$SSH_TTY,CMD=\$command)\";}'" > /etc/profile.d/history.shsource /etc/profile（2.添加普通用户，设置sudo权限#!/bin/bashDate=`date -d now +%Y%m%d%H%M%S`dir=/etc#输入用户id，用户名，密码uid=511name=chaorenmima=chaorenbuhuifei useradd -u $uid $nameecho "$mima" | passwd --stdin $nameecho "$name add ok,密码 $mima " cp $dir/sudoers $dir/sudoers-${Date}.bakchmod u+w $dir/sudoerssed -i '/^root/a '$name' \tALL=(ALL)\tNOPASSWD:ALL' $dir/sudoers#echo "'$name'  ALL=(ALL)    NOPASSWD:ALL">>$dir/sudoerschmod u-w $dir/sudoersecho "${name} sudo 权限添加成功"（3.关闭selinux（4.配置iptables（5.禁止root远程用户登录（6.修改远程端口#!/bin/bashDate=`date -d now +%Y%m%d%H%M%S` chkconfig --list|grep iptableschkconfig iptables off cp /etc/sysconfig/iptables /etc/sysconfig/iptables_$Datesed -i '/--dport 22/a -A INPUT -m state --state NEW -m tcp -p tcp --dport 5959 -j ACCEPT' /etc/sysconfig/iptablesservice iptables stop setenforce 0sed -i -e 's|SELINUX=enforcing|SELINUX=disabled|' /etc/sysconfig/selinux cp /etc/ssh/sshd_config /etc/ssh/sshd_config_$Datesed -i '/#Port 22/i Port 5959' /etc/ssh/sshd_configsed -i '/#PermitRootLogin/i PermitRootLogin no' /etc/ssh/sshd_configservice sshd restart（7.精简开机启动服务器（8.修改最大连接数 ulimit（9.禁止使用Ctrl+Alt+Del快捷键重启服务器（10.修改默认DNS#!/bin/bashDate=`date -d now +%Y%m%d%H%M%S`for server in `chkconfig --list|egrep -v 'crond|network|rsyslog|sshd|iptables'|awk '{print $1}'`;do chkconfig $server off; donecp /etc/security/limits.conf /etc/security/limits.conf_$Dateecho '*  -  noproc  65535' >> /etc/security/limits.confecho '*  -  nofile  65535' >> /etc/security/limits.conf cp /etc/init/control-alt-delete.conf /etc/init/control-alt-delete.conf_$Datesed -i "s/start on control-alt-delete/#start on control-alt-delete/g"  /etc/init/control-alt-delete.conf cp /etc/resolv.conf /etc/resolv.conf_$Dateecho "nameserver 202.106.0.20" > /etc/resolv.confecho "nameserver 8.8.4.4" >> /etc/resolv.conf（11.优化内核参数 [根据实际情况调整]#!/bin/bashDate=`date -d now +%Y%m%d%H%M%S` cp /etc/sysctl.conf /etc/sysctl.conf_$Date echo -e "net.core.somaxconn = 262144" >> /etc/sysctl.confecho -e "net.core.netdev_max_backlog = 262144" >> /etc/sysctl.confecho -e "net.core.wmem_default = 8388608" >> /etc/sysctl.confecho -e "net.core.rmem_default = 8388608" >> /etc/sysctl.confecho -e "net.core.rmem_max = 16777216" >> /etc/sysctl.confecho -e "net.core.wmem_max = 16777216" >> /etc/sysctl.confecho -e "net.ipv4.route.gc_timeout = 20" >> /etc/sysctl.confecho -e "net.ipv4.ip_local_port_range = 1024 65535" >> /etc/sysctl.confecho -e "net.ipv4.tcp_retries2 = 5" >> /etc/sysctl.confecho -e "net.ipv4.tcp_fin_timeout = 30" >> /etc/sysctl.confecho -e "net.ipv4.tcp_syn_retries = 1" >> /etc/sysctl.confecho -e "net.ipv4.tcp_synack_retries = 1" >> /etc/sysctl.confecho -e "net.ipv4.tcp_timestamps = 0" >> /etc/sysctl.confecho -e "net.ipv4.tcp_tw_recycle = 1" >> /etc/sysctl.confecho -e "net.ipv4.tcp_tw_reuse = 1" >> /etc/sysctl.confecho -e "net.ipv4.tcp_keepalive_time = 120" >> /etc/sysctl.confecho -e "net.ipv4.tcp_keepalive_probes = 3" >> /etc/sysctl.confecho -e "net.ipv4.tcp_keepalive_intvl = 15" >> /etc/sysctl.confecho -e "net.ipv4.tcp_max_tw_buckets = 36000" >> /etc/sysctl.confecho -e "net.ipv4.tcp_max_orphans = 3276800" >> /etc/sysctl.confecho -e "net.ipv4.tcp_max_syn_backlog = 262144" >> /etc/sysctl.confecho -e "net.ipv4.tcp_wmem = 8192 131072 16777216" >> /etc/sysctl.confecho -e "net.ipv4.tcp_rmem = 32768 131072 16777216" >> /etc/sysctl.confecho -e "net.ipv4.tcp_mem = 94500000 915000000 927000000" >> /etc/sysctl.confecho -e "net.ipv4.tcp_slow_start_after_idle = 0" >> /etc/sysctl.confecho -e "vm.swappiness = 0" >> /etc/sysctl.confecho -e "kernel.panic = 5" >> /etc/sysctl.confecho -e "kernel.panic_on_oops = 1" >> /etc/sysctl.conf  echo -e "kernel.core_pipe_limit = 0" >> /etc/sysctl.conf#iptables 防火墙echo -e "net.nf_conntrack_max = 25000000" >> /etc/sysctl.confecho -e "net.netfilter.nf_conntrack_max = 25000000" >> /etc/sysctl.confecho -e "net.netfilter.nf_conntrack_tcp_timeout_established = 180" >> /etc/sysctl.confecho -e "net.netfilter.nf_conntrack_tcp_timeout_time_wait = 120" >> /etc/sysctl.confecho -e "net.netfilter.nf_conntrack_tcp_timeout_close_wait = 60" >> /etc/sysctl.confecho -e "net.netfilter.nf_conntrack_tcp_timeout_fin_wait = 120" >> /etc/sysctl.conf modprobe bridgeecho "modprobe bridge">> /etc/rc.local sysctl -p