防火墙
netfilter/iptables IP 信息包过滤系统
netfilter
内核空间（kernelspace），是内核的一部分，由一些信息包过滤表组成，这些表包含内核用来控制信息包过滤处理的规则集。
即：存放内核过滤规则的防火墙
iptables
用户空间（userspace），用于增删改信息包过滤表中规则的工具，指向netfiler网络过滤子系统
基于接口设置规则
即：用户管理防火墙的工具
静态防火墙
单独更改意味着清除就规则和从配置文件读取所有新规则
配置文件路径：/etc/sysconfig/iptables
firewalld
也属于用户态的管理防火墙的工具，定义防火墙的各种规则功能
基于区域设置规则，根据源IP和流入网络接口将网络流量分开流入不同区域，类似于window的公用家用网
动态防火墙
不创建新规则，仅运行规则的不同之处，可以改变设置不丢失现行连接
区域优先级：源地址绑定区域>网卡绑定区域>默认区域
配置文件路径：/etc/firewalld（优先加载）和/usr/lib/firewalld（默认的配置文件）中的各个配置文件xml
|
区域
|
允许传入流量的预定义服务 |
说明 |
trusted
信任区域 |
允许所有 |
|
public
公共区域 |
ssh
dhcpv6-client |
新加网络接口的默认区域 |
external
外部区域 |
ssh |
默认将通过此区域的ipv4传出流量地址伪装，用于为路由器启动伪装功能的外部网络 |
home
家庭区域 |
ssh
mdns
samba-client
dhcpv6-client |
|
internal
内部区域 |
默认值时同home区域 |
|
work
工作区域 |
ssh
dhcpv6-client |
|
dmz
隔离区域 |
ssh |
|
block
限制区域 |
拒绝所有 |
|
drop
丢弃区域 |
丢弃传入流量 |
没有ICMP错误响应 |
网络
ip
ip route
Ethernet：以太网
eth0: 第一块以太网卡
via：通过
dev：设备
default via 192.168.60.1 dev eth0
192.168.60.0/24 dev eth0 proto kernel scope link src 192.168.60.2
默认网关通过地址为第一块以太网卡设备IP=192.168.60.1
子网掩码，也就是网段范围：循环192.168.60.0~192.168.60.254
本机ip=192.168.60.2
修改镜像源（ubuntu为例）
注意：进入网站选择对应ubuntu版本拷贝,如清华源
1.备份
cp -a /etc/apt/sources.list /etc/apt/sources.list.bak
2.vim编辑修改
或命令：
sudo sed -i "s@http://.*archive.ubuntu.com@https://mirrors.tuna.tsinghua.edu.cn@g" /etc/apt/sources.list
sudo sed -i "s@http://.*security.ubuntu.com@https://mirrors.tuna.tsinghua.edu.cn@g" /etc/apt/sources.list
注意：[trusted=yes]可忽略警告，如
deb [trusted=yes] https://mirrors.ustc.edu.cn/ubuntu/ impish main restricted universe multiverse
# 中科大镜像源
deb https://mirrors.ustc.edu.cn/ubuntu/ impish main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ impish main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ impish-updates main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ impish-updates main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ impish-backports main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ impish-backports main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ impish-security main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ impish-security main restricted universe multiverse
deb https://mirrors.ustc.edu.cn/ubuntu/ impish-proposed main restricted universe multiverse
deb-src https://mirrors.ustc.edu.cn/ubuntu/ impish-proposed main restricted universe multiverse
# 清华镜像源
https://mirrors.tuna.tsinghua.edu.cn/help/ubuntu/
# 阿里镜像源
deb [trusted=yes] http://mirrors.aliyun.com/ubuntu/ impish main restricted universe multiverse
deb-src [trusted=yes] http://mirrors.aliyun.com/ubuntu/ impish main restricted universe multiverse
deb [trusted=yes] http://mirrors.aliyun.com/ubuntu/ impish-security main restricted universe multiverse
deb-src [trusted=yes] http://mirrors.aliyun.com/ubuntu/ impish-security main restricted universe multiverse
deb [trusted=yes] http://mirrors.aliyun.com/ubuntu/ impish-updates main restricted universe multiverse
deb-src [trusted=yes] http://mirrors.aliyun.com/ubuntu/ impish-updates main restricted universe multiverse
deb [trusted=yes] http://mirrors.aliyun.com/ubuntu/ impish-proposed main restricted universe multiverse
deb-src [trusted=yes] http://mirrors.aliyun.com/ubuntu/ impish-proposed main restricted universe multiverse
deb [trusted=yes] http://mirrors.aliyun.com/ubuntu/ impish-backports main restricted universe multiverse
deb-src [trusted=yes] http://mirrors.aliyun.com/ubuntu/ impish-backports main restricted universe multiverse
# 163镜像源
deb http://mirrors.163.com/ubuntu/ impish main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ impish main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ impish-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ impish-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ impish-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ impish-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ impish-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ impish-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ impish-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ impish-backports main restricted universe multiverse
3.更新
sudo apt-get update
sudo apt-get upgrade
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