ufw-{deny, allow}: add ufw-deny page and update ufw-allow (#23425)

pages/linux/ufw-allow.md

@@ -5,24 +5,28 @@
 
 - Allow all traffic on a port:
 
-`ufw allow {{port}}`
+`sudo ufw allow {{port}}`
 
 - Allow traffic for a protocol on a port:
 
-`ufw allow {{port}}/{{protocol}}`
+`sudo ufw allow {{port}}/{{protocol}}`
 
 - Allow incoming traffic for a protocol and add a comment for documentation:
 
-`ufw allow in {{protocol}} comment '{{comment}}'`
+`sudo ufw allow in {{protocol}} comment '{{comment}}'`
 
 - Allow all traffic from a source address:
 
-`ufw allow from {{source_address}}`
+`sudo ufw allow from {{source_address}}`
+
+- Allow all incoming traffic from the subnet 192.168.13.0/24:
+
+`sudo ufw allow from 192.168.13.0/24`
 
 - Allow TCP traffic from 192.168.1.12 to 192.168.1.100 on port 443:
 
-`ufw allow from 192.168.1.12 to 192.168.1.100 port 443 proto tcp`
+`sudo ufw allow from 192.168.1.12 to 192.168.1.100 port 443 proto tcp`
 
 - Allow all incoming GRE traffic to 192.168.1.100 on the eth0 interface:
 
-`ufw allow in on eth0 to 192.168.1.100 proto gre`
+`sudo ufw allow in on eth0 to 192.168.1.100 proto gre`

pages/linux/ufw-deny.md

@@ -0,0 +1,32 @@
+# ufw deny
+
+> Block traffic through the firewall.
+> More information: <https://manned.org/ufw>.
+
+- Deny all traffic on a port:
+
+`sudo ufw deny {{port}}`
+
+- Deny traffic for a protocol on a port:
+
+`sudo ufw deny {{port}}/{{protocol}}`
+
+- Deny incoming traffic for a protocol and add a comment for documentation:
+
+`sudo ufw deny in {{protocol}} comment '{{comment}}'`
+
+- Deny all traffic from a source address:
+
+`sudo ufw deny from {{source_address}}`
+
+- Deny all incoming traffic from the subnet 192.168.13.0/24:
+
+`sudo ufw deny from 192.168.13.0/24`
+
+- Deny UDP traffic from 192.168.1.12 to 192.168.1.100 on port 8080:
+
+`sudo ufw deny from 192.168.1.12 to 192.168.1.100 port 8080 proto udp`
+
+- Deny all incoming IGMP traffic to 192.168.1.100 on the eth0 interface:
+
+`sudo ufw deny in on eth0 to 192.168.1.100 proto igmp`