centos7簡易優化

centos7系統初始優化

yum install wget net-tools  lrzsz-y

更改yum源

mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo

關閉selinux

sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config
grep SELINUX=disabled /etc/selinux/config
setenforce 0
getenforce

關閉防火牆

/etc/init.d/iptables stop
/etc/init.d/iptables stop
chkconfig iptables off
systemctl stop firewalld
systemctl disable firewalld

提權非root用戶管理

useradd web01
echo XDK910126!|passwd --stdin 123456
\cp /etc/sudoers /etc/sudoers.ori
echo "web01  ALL=(ALL) NOPASSWD: ALL " >>/etc/sudoers
tail -1 /etc/sudoers
visudo -c

時間同步

echo '*/5 * * * * /usr/sbin/ntpdate ntp1.aliyun.com >/dev/null 2>&1' >>/var/spool/cron/root
crontab -l

操作歷史記錄保留行減少

#echo 'export TMOUT=300' >>/etc/profile
#echo 'export HISTSIZE=5' >>/etc/profile
#echo 'export HISTFILESIZE=5' >>/etc/profile
#tail -3 /etc/profile
#. /etc/profile

文件描述符增加

echo '*               -       nofile          65535 ' >>/etc/security/limits.conf 
tail -1 /etc/security/limits.conf 

內核基礎優化

cat >>/etc/sysctl.conf<<EOF
fs.file-max = 65535
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_port_range = 4000    65000
net.ipv4.tcp_max_syn_backlog = 16384
net.ipv4.tcp_timestamps = 0
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
###disable ping
#net.ipv4.icmp_echo_ignore_all=1
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
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv4.icmp_ignore_bogus_error_responses =1
net.ipv4.icmp_echo_ignore_broadcasts = 1
kernel.sysrq = 0
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
net.ipv4.tcp_max_orphans = 3276800
EOF

補充幾個工具

yum install lrzsz nmap tree dos2unix nc -y

ssh連接優化

#sed -i '13aPort 52013' /etc/ssh/sshd_config
sed -i 's#GSSAPIAuthentication yes#GSSAPIAuthentication no#g' /etc/ssh/sshd_config
sed -i '123aUseDNS yes' /etc/ssh/sshd_config

service sshd reload