ubuntu.md

Ubuntu tips

Network

Firewall

1. Enable ufw (Uncomplicated Firewall)

   $ ufw enable
   

2. Check status / applied rules

   $ ufw status
   Status: active
   
   To                         Action      From
   --                         ------      ----
   22/tcp                     ALLOW       Anywhere
   22/tcp (v6)                ALLOW       Anywhere (v6)
   

3. Allow connections

   $ ufw allow ssh
   $ ufw allow 53825/udp
   

4. Detele rules

   $ ufw delete allow ssh
   $ ufw status numbered
   $ ufw delete [number]
   

5. Allow routing

   $ ufw route allow in on eth0 out on eth1 to 12.34.45.67 port 80 proto tcp
   $ ufw route allow in on eth1 out on eth2
   $ sysctl -w net/ipv4/ip_forward=1
   $ sysctl -w net/ipv6/conf/default/forwarding=1
   $ sysctl -w net/ipv6/conf/all/forwarding=1
   

Enable SSH

$ systemctl enable ssh