1）關閉selinux

使用getenforce 可以查看selinux的狀態

[[email protected] ~]$ getenforce

Enforcing

或者使用sestatus

[[email protected] ~]# sestatus

SELinux status: enabled

SELinuxfs mount: /sys/fs/selinux

SELinux root directory: /etc/selinux

Loaded policy name: targeted

Current mode: permissive

Mode from config file: enforcing

Policy MLS status: enabled

Policy deny_unknown status: allowed

Max kernel policy version: 28

使用setenforce 0臨時關閉selinux（為寬容模式Permissive）

[[email protected] ~]# setenforce 0

[[email protected] ~]# getenforce

Permissive

要永久關閉操作如下（紅色為修改部分）

[[email protected] ~]# vi /etc/selinux/config

# This file controls the state of SELinux on the system.

# SELINUX= can take one of these three values:

# enforcing - SELinux security policy is enforced.

# permissive - SELinux prints warnings instead of enforcing.

# disabled - No SELinux policy is loaded.

SELINUX=disabled

# SELINUXTYPE= can take one of three two values:

# targeted - Targeted processes are protected,

# minimum - Modification of targeted policy. Only selected processes are protected.

# mls - Multi Level Security protection.

SELINUXTYPE=targeted

註意修改後要重啟服務器然後再查看一下狀態

[[email protected] ~]$ sestatus

SELinux status: disabled

2）關閉防火墻

註意：centos7的防火墻默認使用的是firewalld

臨時關閉防火墻

[[email protected] ~]$ systemctl stop firewalld.service

永久關閉防火墻

[[email protected] ~]$ systemctl disable firewalld.service

Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.

Removed symlink /etc/systemd/system/basic.target.wants/firewalld.service.

查看防火墻的狀態

[[email protected] ~]$ firewall-cmd --state

not running

3）基本優化

修改最大打開進程數和最大文件句柄，先使用ulimit命令查看

[[email protected] ~]# ulimit -n

1024

[[email protected] ~]# ulimit -u

3480

修改相關的配置

[[email protected] ~]# vi /etc/security/limits.conf

在最後追加下面幾行

* soft nofile 1024000

* hard nofile 1024000

* soft nproc 1024000

* hard nproc 1024000

再修改/etc/security/limits.d下的文件20-nproc.conf (紅色為修改項 已修改)

[[email protected] ~]# vi /etc/security/limits.d/20-nproc.conf

# Default limit for number of user‘s processes to prevent

# accidental fork bombs.

# See rhbz #432903 for reasoning.

* soft nproc 1024000

* hard nproc 1024000

註意：修改完成後重啟生效

內核基礎優化配置，（暫時不太懂，先直接操作即可）

[[email protected] sysctl.d]# vi /usr/lib/sysctl.d/ 00-system.conf

追加下面的參數

#關閉ipv6

net.ipv6.conf.all.disable_ipv6 = 1

net.ipv6.conf.default.disable_ipv6 = 1

# 避免放大攻擊

net.ipv4.icmp_echo_ignore_broadcasts = 1

# 開啟惡意icmp錯誤消息保護

net.ipv4.icmp_ignore_bogus_error_responses = 1

#關閉路由轉發

net.ipv4.ip_forward = 0

net.ipv4.conf.all.send_redirects = 0

net.ipv4.conf.default.send_redirects = 0

#開啟反向路徑過濾

net.ipv4.conf.all.rp_filter = 1

net.ipv4.conf.default.rp_filter = 1

#處理無源路由的包

net.ipv4.conf.all.accept_source_route = 0

net.ipv4.conf.default.accept_source_route = 0

#關閉sysrq功能

kernel.sysrq = 0

#core文件名中添加pid作為擴展名

kernel.core_uses_pid = 1

# 開啟SYN洪水攻擊保護

net.ipv4.tcp_syncookies = 1

#修改消息隊列長度

kernel.msgmnb = 65536

kernel.msgmax = 65536

#設置最大內存共享段大小bytes

kernel.shmmax = 68719476736

kernel.shmall = 4294967296

#timewait的數量，默認180000

net.ipv4.tcp_max_tw_buckets = 6000

net.ipv4.tcp_sack = 1

net.ipv4.tcp_window_scaling = 1

net.ipv4.tcp_rmem = 4096 87380 4194304

net.ipv4.tcp_wmem = 4096 16384 4194304

net.core.wmem_default = 8388608

net.core.rmem_default = 8388608

net.core.rmem_max = 16777216

net.core.wmem_max = 16777216

#每個網絡接口接收數據包的速率比內核處理這些包的速率快時，允許送到隊列的數據包的最大數目

net.core.netdev_max_backlog = 262144

#限制僅僅是為了防止簡單的DoS 攻擊

net.ipv4.tcp_max_orphans = 3276800

#未收到客戶端確認信息的連接請求的最大值

net.ipv4.tcp_max_syn_backlog = 262144

net.ipv4.tcp_timestamps = 0

#內核放棄建立連接之前發送SYNACK 包的數量

net.ipv4.tcp_synack_retries = 1

#內核放棄建立連接之前發送SYN 包的數量

net.ipv4.tcp_syn_retries = 1

#啟用timewait 快速回收

net.ipv4.tcp_tw_recycle = 1

#開啟重用。允許將TIME-WAIT sockets 重新用於新的TCP 連接

net.ipv4.tcp_tw_reuse = 1

net.ipv4.tcp_mem = 94500000 915000000 927000000

net.ipv4.tcp_fin_timeout = 1

#當keepalive 起用的時候，TCP 發送keepalive 消息的頻度。缺省是2 小時

net.ipv4.tcp_keepalive_time = 30

#允許系統打開的端口範圍

net.ipv4.ip_local_port_range = 1024 65000

#修改防火墻表大小，默認65536

#net.netfilter.nf_conntrack_max=655350

#net.netfilter.nf_conntrack_tcp_timeout_established=1200

# 確保無人能修改路由表

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

使其生效

[[email protected] sysctl.d]# sysctl -p

4）簡化開機服務

這個暫時先不搞

5）做個快捷設置網絡腳本

先配置下centos7的網絡 首先使用ip命令查看下狀態

[[email protected] network-scripts]# ip addr

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

valid_lft forever preferred_lft forever

2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000

link/ether 00:0c:29:36:ff:fd brd ff:ff:ff:ff:ff:ff

inet 192.168.0.101/24 brd 192.168.0.255 scope global ens33

valid_lft forever preferred_lft forever

3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN qlen 1000

link/ether 52:54:00:bd:63:40 brd ff:ff:ff:ff:ff:ff

inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0

valid_lft forever preferred_lft forever

4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN qlen 1000

link/ether 52:54:00:bd:63:40 brd ff:ff:ff:ff:ff:ff

上面出現了3和4.這個我不知道是怎麽回事，網上查了下，有幹掉的辦法，貼出來如下

到這裏看起來就正常多了，最後配置下

vi /etc/sysconfig/network-scripts/ifcfg-ens33

TYPE="Ethernet"

BOOTPROTO=static

DEFROUTE="yes"

IPV4_FAILURE_FATAL="no"

IPV6INIT="yes"

IPV6_AUTOCONF="yes"

IPV6_DEFROUTE="yes"

IPV6_FAILURE_FATAL="no"

IPV6_ADDR_GEN_MODE="stable-privacy"

NAME=ens33

UUID="06ce2307-5a1c-4624-8a7a-f1ba1fd87458"

DEVICE=ens33

ONBOOT="yes"

DNS1=202.102.224.68

IPADDR0=192.168.0.10

PREFIX=24

GATEWAY0=192.168.0.1

IPV6_PEERDNS=yes

IPV6_PEERROUTES=yes

IPV6_PRIVACY=no

重啟網絡（有幾種重啟的方法，centos7推薦使用的是下面的方式，而且使用久方式可能會給你轉發請求到此命令 無返回值即為最好的結果）

[[email protected] network-scripts]# systemctl restart network.service

[[email protected] network-scripts]#

基本上完成以上操作既可以正常使用了，我使用此模板作為克隆源，所以寫一個簡單的腳本來方便的進行ip修改>>>>>

編寫腳本：

創建一個腳本目錄並創建一個簡單的更換ip的腳本

[[email protected] /]# mkdir /home/snail/scripts

[[email protected] /]# cd /home/snail/scripts

[[email protected] scripts]# touch ipcrt:wq

[[email protected] scripts]# chmod +x ipcrt

[[email protected] scripts]# vi ~/.bashrc

# .bashrc

# User specific aliases and functions

alias rm=‘rm -i‘

alias cp=‘cp -i‘

alias mv=‘mv -i‘

# Source global definitions

if [ -f /etc/bashrc ]; then

. /etc/bashrc

fi

#這裏要註意，要把環境變量寫入這個文件下，不然重啟失效

PATH="/home/snail/scripts:$PATH"

[[email protected] scripts]# ll

total 0

-rwxr-xr-x 1 root root 0 Aug 29 15:42 ip_create.sh

[[email protected] scripts]# vi ipcrt

沒有進行參數校驗，需要註意，參數必須寫正確，否則會出問題。

#! /bin/sh

sed -i ‘/IPADDR.*/d‘ /etc/sysconfig/network-scripts/ifcfg-ens33

echo ‘IPADDR0‘=$1>>/etc/sysconfig/network-scripts/ifcfg-ens33

systemctl restart network.service

改版之後的腳本

[[email protected] scripts]# cat ipcrt

#! /bin/bash

#對參數進行判斷

case "$1" in

--help)

echo "please enter an IP address !"

echo "Scope in 192.168.0.10 - 192.168.0.99";;

*)

if [[ ${#1} -eq 12 ]];then

sed -i ‘/IPADDR.*/d‘ /etc/sysconfig/network-scripts/ifcfg-ens33

echo ‘IPADDR0‘=$1>>/etc/sysconfig/network-scripts/ifcfg-ens33

systemctl restart network.service

sleep 1

echo "ip changed ok!"

else

echo "error:input error!"

echo ‘please enter a "--help" view the help information!‘

fi

;;

esac

創建一個更換主機名的腳本（只適用centos7）

#! /bin/bash

hostnamectl set-hostname $1

sed -i ‘/127.0.0.1*/d‘ /etc/hosts

echo "127.0.0.1 " $1 $1 >>/etc/hosts

6）更換yum源

默認使用的是sohu源，看了下裏面貌似只支持4,5的版本，所以更改為163的源 地址：mirrors.163.com

[[email protected] ~]# cd /etc/yum.repos.d/

[[email protected] yum.repos.d]# mv CentOS-Base.repo CentOS-Base.repo.old

[[email protected] yum.repos.d]# wget http://mirrors.163.com/.help/CentOS7-Base-163.repo

......

[[email protected] yum.repos.d]# mv CentOS7-Base-163.repo CentOS-Base.repo

[[email protected] yum.repos.d]# yum clean all

[[email protected] yum.repos.d]# yum makecache

7）時間同步

查看系統時間

[[email protected] ~]$ date

Mon Aug 28 23:05:20 PDT 2017

查看時區並修改

[[email protected] ~]# date -R （方法1）

Mon, 28 Aug 2017 23:12:35 -0700

[[email protected] ~]# date +%z （方法2）

-0700

[[email protected] ~]# cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

cp: overwrite ‘/etc/localtime’? y

安裝時間同步工具

[[email protected] ~]# yum -y install ntp ntpdate

同步時間

[[email protected] ~]# ntpdate cn.pool.ntp.org

設置定時更新時間任務

[[email protected] ~]# echo ‘*/10 * * * * /usr/sbin/ntpdate time.nist.gov >/dev/null 2>&1‘ >>/var/spool/cron/root

本文出自 “不懈的蝸牛” 博客，請務必保留此出處http://songxiao.blog.51cto.com/12183698/1961175

centos7 新安裝基礎配置