Ufw on debian

on my kali2020 laptop

#on my laptop
sudo apt install ufw

sudo ufw default deny incoming

 sudo ufw default allow outgoing
  
 sudo ufw allow ssh
  
 #is a web 
  sudo ufw allow 80
   sudo ufw allow 443 
 
 #Firewall is active and enabled on system startup
 sudo ufw enable

sudo ufw status

线上一般的结合操作

apt  install ufw 
ufw enable 

sudo ufw default allow outgoing
sudo ufw default deny incoming

 ufw  allow ssh 
 ufw  allow  www

etc 


正常返回如下 

 ufw  status 
Status: active

To                         Action      From
--                         ------      ----
SSH                        ALLOW       Anywhere                  
80/tcp                     ALLOW       Anywhere                  
SSH (v6)                   ALLOW       Anywhere (v6)             
80/tcp (v6)                ALLOW       Anywhere (v6)  

* install

apt  install ufw

* Configuration

 ufw enable 
Command may disrupt existing ssh connections. Proceed with operation (y|n)? y
Firewall is active and enabled on system startup


UFW’s defaults are to deny all incoming connections and allow all outgoing connections.

要确定ufw  status 后有没有规则可见 

可见 这两个不要手工执行了 默认就有的 现执行就可以连ssh都上不去了 
ufw default deny incoming
ufw default allow outgoing

ufw status verbose

* Firewall Rules

 ufw app list
 

 ufw  allow 'SSH'
ufw  allow  22/tcp
 ufw  allow WWW #其实就是80

 
 
 ufw allow 'Nginx HTTP'


ufw allow 53/tcp 

** Port Ranges

Port ranges may also be specified, a simple example for tcp would be:

  ufw allow 1000:2000/tcp

and for udp:

  ufw allow 1000:2000/udp

** IP address

An IP address may also be used:

 ufw allow from 111.222.333.444

* Deleting Rules

Rules may be deleted with the following command:

 ufw delete allow ssh

ufw reset

开启/禁用相应端口或服务举例

sudo ufw allow 80 #允许外部访问80端口
sudo ufw delete allow 80 #禁止外部访问80 端口
sudo ufw allow from 192.168.1.1 #允许此IP访问所有的本机端口
sudo ufw deny smtp #禁止外部访问smtp服务，#以服务名代表端口，可以使用less /etc/services列出所有服务信息, 其中包括该服务使用了哪个端口和哪种协议
sudo ufw delete allow smtp #删除上面建立的某条规则，或者sudo ufw delete allow 80/tcp，如果出现无法删除，可以用序号：sudo ufw status numbered，然后通过序号删除sudo ufw delete 1
sudo ufw deny proto tcp from 10.0.0.0/8 to 192.168.0.1 port 22 #要拒绝所有的TCP流量从10.0.0.0/8 到192.168.0.1地址的22端口
#可以允许所有RFC1918网络（局域网/无线局域网的）访问这个主机（/8,/16,/12是一种网络分级）：
sudo ufw allow from 10.0.0.0/8
sudo ufw allow from 172.16.0.0/12
sudo ufw allow from 192.168.0.0/16

troubleshooting

openssh都连接上去 

这个导致上不了的 
 ufw default deny incoming


确定了 不是这个问题  是 
ufw  status verbose 
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing), disabled (routed)
New profiles: skip

To                         Action      From
--                         ------      ----
22/tcp (SSH)               ALLOW IN    Anywhere                  
80/tcp (WWW)               ALLOW IN    Anywhere                  
22/tcp (SSH (v6))          ALLOW IN    Anywhere (v6)             
80/tcp (WWW (v6))          ALLOW IN    Anywhere (v6)   
没有东西  

linode 文档得了

如何确定在 ssh这后再deny incoming 呢  参考iptalbes ?

* see also

https://wiki.debian.org/Uncomplicated%20Firewall%20%28ufw%29

https://www.linode.com/docs/security/firewalls/configure-firewall-with-ufw/

https://help.ubuntu.com/community/UFW

https://www.digitalocean.com/community/tutorials/how-to-setup-a-firewall-with-ufw-on-an-ubuntu-and-debian-cloud-server

ubuntu ufw 防火墙