linux一键优化（适用于RedHat以及衍生版）
#!/bin/bash
#set env
export LANG="en_US.UTF-8"
export PATH=$PATH:/bin/sbin:/usr/sbin
#whether root to running user
if [[ $(whoami) != root ]];then
echo "please su - root run the script."
fi
SERVICE=`which service`
CHKCONFIG=`which chkconfig`
. /etc/init.d/functions
#set time
initTime(){
yum -y install ntpdate > /dev/null 2>&1
ntpdate asia.pool.ntp.org > /dev/null 2>&1
echo "*/5 * * * * ntpdate asia.pool.ntp.org >> /var/spool/cron/root 2> /dev/null" > /var/spool/cron/root 2> /dev/null
[ $? -eq 0 ] && action "initTime is ok " /bin/true || exit 1
sleep 3
}
#install packages
initTool(){
yum -y install sysstat net-snmp lrzsz sar gcc gcc-c++ > /dev/vull 2>&1
yum groupinstall "Compatibility libraries" "Base" "Development tools" > /dev/null 2>&1
yum groupinstall "debugging Tools" "Dial-up Networking Support" >/dev/null 2>&1
[ $? -eq 0 ] && action "initTool is ok " /bin/true || exit 1
sleep 3
}
#update the system lang
initI18n(){
cat /etc/sysconfig/i18n > /etc/sysconfig/i18n.bak
echo LANG="en_US.UTF-8" >> /etc/sysconfig/i18n
source /etc/sysconfig/i18n
[ $? -eq 0 ] && action "initI18n is ok.." /bin/true || exit 1
sleep 3
}
#start iptables
initSelinux(){
selinux="`/usr/sbin/getenforce`"
cat /etc/selinux/config > /etc/selinux/config.bak
[ $selinux != "Disabled" ] && /usr/sbin/setenforce 0 > /dev/null 2>& 1 || echo "selinux is ok... "
sleep 3
}
#close not need to service
initService(){
export LANG="en_US.UTF-8"
for i in `chkconfig --list | grep -i "3:on" | awk '{print $1}'`;do chkconfig $i off; done
for i in crond network rsyslog sshd;do chkconfig --level 3 $i on;done
[ $? -eq 0 ] && action "initService is ok.." /bin/true || exit 1
sleep 3
}
#youhua for ssh
initSsh(){
cat /etc/ssh/sshd_config > /etc/ssh/sshd_config.bak
useradd user > /dev/null 2>&1
echo "feb803873cc1401f" | passwd --stdin user
sed -i 's/#Port 22/Port 22/' /etc/ssh/sshd_config
sed -i 's/#PermitRootLogin yes/PermitRootLogin yes/' /etc/ssh/sshd_config
sed -i 's/#PermitEmptyPasswords no/PermitEmptyPasswords no/' /etc/ssh/sshd_config
/etc/init.d/sshd stop > /dev/null 2>& 1
[ $? -eq 0 ] || exit 1
/etc/init.d/sshd start > /dev/null 2>& 1
[ $? -eq 0 ] && action "initSsh is ok.." || exit 1
}
#change file inode
openFiles(){
cat /etc/security/limits.conf > /etc/security/limits.conf.bak
echo "ulimit -HSn 65535" >> /etc/security/limits.conf
[ $? -eq 0 ] && action "limit is ok" /bin/true || exit 1
sleep 3
}
#youhua kernel
openKernel(){
modprobe bridge > /dev/null 2>& 1
cat /etc/sysctl.conf > /etc/sysctl.conf.bak
cat >> /etc/sysctl.conf << EOF
########################################################
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.icmp_ignore_bogus_error_responses = 1
net.ipv4.tcp_syncookies = 1
net.ipv4.conf.all.log_martians = 1
net.ipv4.conf.default.log_martians = 1
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.default.secure_redirects = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
kernel.exec-shield = 1
kernel.randomize_va_space = 1
fs.file-max = 65535
kernel.pid_max = 65536
net.core.netdev_max_backlog = 4096
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_max_syn_backlog = 4096
net.ipv4.tcp_max_tw_buckets = 4096
net.ipv4.tcp_keepalive_time = 20
net.ipv4.ip_forward = 0
net.ipv4.tcp_mem = 192000 300000 732000
net.ipv4.tcp_rmem = 51200 131072 204800
net.ipv4.tcp_wmem = 51200 131072 204800
net.ipv4.tcp_keepalive_timenet.ipv4.tcp_keepalive_time = 20
net.ipv4.tcp_keepalive_intvl = 5
net.ipv4.tcp_keepalive_probes = 2
net.ipv4.tcp_orphan_retries = 3
net.ipv4.tcp_syn_retries = 3
net.ipv4.tcp_synack_retries = 3
net.ipv4.tcp_retries2 = 5
net.ipv4.tcp_fin_timeout = 30
net.ipv4.tcp_max_orphans = 2000
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
vm.min_free_kbytes=409600
vm.vfs_cache_pressure=200
vm.swappiness = 40
vm.dirty_expire_centisecs = 1500
vm.dirty_writeback_centisecs = 1000
vm.dirty_ratio = 20
vm.dirty_background_ratio = 100
######################################################
EOF
/sbin/sysctl -p > /dev/null 2>& 1
[ $? -eq 0 ] && action "kernel is ok" /bin/true || exit 1
sleep 1
}
#init_snmp
init_snmp(){
cp /etc/snmp/snmpd.conf /etc/snmp/snmpd.conf.bak
sed -i 's/#view all/view all/' /etc/snmp/snmpd.conf
sed -i 's/#access MyROGroup/access MyROGroup/' /etc/snmp/snmpd.conf
${CHKCONFIG} snmpd on > /dev/null 2>&1
${SERVICE} snmpd start > /dev/null 2>&1
[ $? -eq 0 ] && action "snmpd is starting" /bin/true || exit 0
}
initdos(){
echo 180 > /proc/sys/net/ipv4/tcp_keepalive_time
echo 2 > /proc/sys/net/ipv4/tcp_keepalive_probes
echo 2048 > /proc/sys/net/ipv4/tcp_max_syn_backlog
echo 1 > /proc/sys/net/ipv4/tcp_synack_retries
echo 1 > /proc/sys/net/ipv4/tcp_syn_retries
echo 1 > /proc/sys/net/ipv4/tcp_syncookies
[ $? -eq 0 ] && action "snmpd is starting" /bin/true || exit 0
}
initTime
initTool
initI18n
initSelinux
initService
initSsh
openFiles
openKernel
init_snmp
initdos
echo "Don't forget start your iptables."