Ufw-next simple firewall in linux

Ufw & mdash; the next simple firewall ufw in linux is an administrator tool. Ufw man documentation already contains a wide range of examples, such as 01Userscanspecifyrulesusingeitherasimplesyntaxorafullsyntax02Thesimplesynt ufw-linux's next simple firewall ufw is an administrator tool. Ufw man documents have rich examples, such: 01 Users can specify rules using either a simple syntax or a full syntax.02 The simple syntax only specifies the port and optionally the protocol to03 be allowed or denied on the host. for example: 04 05 ufw allow 5306 07 This rule will allow tcp and udp port 53 to any address on this host. to08 specify a protocol, append '/protocol' to the port. for example: 09 10 ufw allow 25 /Tcp11 12 This will allow tcp port 25 to any address on this host. ufw will also13 check/etc/services for the port and protocol if specifying a service by14 name. eg: 15 16 ufw allow smtp17 18 ufw supports both ingress and egress filtering and users may optionally19 specify a ction of either in or out for either incoming or outgoing20 traffic. if no direction is supplied, the rule applies to I Ncoming traf? 21 fic. Eg: 22 23 ufw allow in http24 ufw reject out smtp25 26 Users can also use a fuller syntax, specifying the source and destina? 27 tion addresses and ports. this syntax is based on OpenBSD's PF syntax.28 For example: 29 30 ufw deny proto tcp to any port 8031 32 This will deny all traffic to tcp port 80 on this host. another example: 33 34 ufw deny proto tcp from 10.0.0.0/8 to 192.168.0.1 port 2535 36 This will deny all traffic from the RFC1918 Class A network to tcp port37 25 with the address 192.168.0.1.38 39 ufw deny proto Tcp from 2001: db8:/32 to any port 2540 41 This will deny all traffic from the IPv6 2001: db8:/32 to tcp port 25 on42 this host. note that IPv6 must be enabled in/etc/default/ufw for IPv643 firewalling to work.44 45 ufw allow proto tcp from any to any port 80,443,808 0: 809046 47 The above will allow all traffic to tcp ports 80,443 and 8080-809048 intrusive. note that when specifying multiple port S, the ports list49 must be numeric, cannot contain spaces and must be modified as a whole.50 Eg, in the above example you cannot later try to delete just the '100' 51 port. you cannot specify more than 15 ports (ranges count as 2 ports, so52 the port count in the above example is 4 ). example: 01 $ ufw status02ERROR: You need to be root to run this script03 04 $ ufw deny 80/tcp05ERROR: You need to be roo T to run this script06 07 $ sudo ufw deny 80/tcp08 [sudo] password for sunlt: 09 Rules updated10Rules updated (v6) 11 12 $ sudo ufw status13Status: inactive14 15 $ sudo ufw enable16Firewall is active and enabled on system startup17 18 $ sudo ufw status19Status: active20 21To Action From22 -- ------ ---- 2380/tcp DENY Anywhere2480/tcp DENY Anywhere (v6) 25 26 27 $ sudo ufw status numbered28Status: active29 30 To Action From31 -- ------ ---- 32 [1] 80/tcp deny in Anywhere33 [2] 80/tcp deny in Anywhere (v6) 34 35 36 $ sudo ufw delete 137 Deleting: 38 deny 80/tcp39Proceed with operation (y | n )? Y40Rule deleted41 42 $ sudo ufw delete 243 ERROR: cocould not find rule '2' 44 45 $ sudo ufw status numbered46Status: active47 48 To Action From49 -- ------ ---- 50 [1] 80/tcp deny in Anywhere (v6) 51 52 53 $ sudo ufw delete 1 54 Deleting: 55 deny 80/tcp56Proceed with operation (y | n )? Y57Rule deleted (v6) 58 59 $ sudo ufw status numbered60Status: active61 62 $ sudo ufw disable63Firewall stopped and disabled on system startup