#!/bin/bash

# Close SELINUX
setenforce 0
sed -i 's/^SELINUX=.*$/SELINUX=disabled/' /etc/selinux/config

# /etc/security/limits.conf
[ -e /etc/security/limits.d/*nproc.conf ] && rename nproc.conf nproc.conf_bk /etc/security/limits.d/*nproc.conf
sed -i '/^# End of file/,$d' /etc/security/limits.conf
cat >> /etc/security/limits.conf <<EOF
# End of file
* soft nproc 65535
* hard nproc 65535
* soft nofile 65535
* hard nofile 65535
EOF

# Set timezone
rm -rf /etc/localtime
ln -s /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

# /etc/sysctl.conf
sed -i 's/net.ipv4.tcp_syncookies.*$/net.ipv4.tcp_syncookies = 1/g' /etc/sysctl.conf
[ -z "`grep 'fs.file-max' /etc/sysctl.conf`" ] && cat >> /etc/sysctl.conf << EOF
fs.file-max = 65535
net.ipv4.tcp_fin_timeout = 30
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 0
net.ipv4.ip_local_port_range = 1024 65000
net.ipv4.tcp_max_syn_backlog = 65536
net.ipv4.tcp_max_tw_buckets = 20000
net.ipv4.route.gc_timeout = 100
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syncookies = 1
net.core.somaxconn = 65535
net.core.netdev_max_backlog = 262144
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_max_orphans = 262144

net.core.rmem_max = 67108864
net.core.wmem_max = 67108864
net.core.rmem_default = 65536
net.core.wmem_default = 65536
net.ipv4.tcp_rmem = 4096 87380 67108864
net.ipv4.tcp_wmem = 4096 65536 67108864
net.ipv4.tcp_mtu_probing = 1
#net.ipv4.tcp_congestion_control = hybla
net.ipv4.tcp_fastopen = 3
EOF
sysctl -p /etc/sysctl.conf

echo "Configuring Firewall..."
sudo systemctl stop firewalld
sudo systemctl mask firewalld
sudo yum install iptables iptables-services -y

sudo /sbin/iptables -I INPUT -p tcp --dport 22 -j ACCEPT
sudo /sbin/service iptables save

sudo systemctl restart iptables
sudo systemctl enable iptables.service