###Create a Single Firewall Rule Using a Subnet Mask

You can create a single firewall rule to block the IP range 13.54.0.0 to 13.54.255.255 using the /16 mask like this:

13.54.0.0/16

The portion after the / is the subnet mask which specifies how many bits of the specified address should be examined to determine if a connection's IP address matches the rule.

In your case it's easy to figure this out. You want to match addresses based only on the first two octets (13.54.x.x) of the IP address. An octet contains 8 bits, so two octets equals 16 bits or a mask of /16.

Find out more on Wikipedia about using a mask of bits to indicate which parts of an IP are matched.

Create a Single Firewall Rule Using a Subnet Mask

You can create a single firewall rule to block the IP range 13.54.0.0 to 13.54.255.255 using the /16 mask like this:

13.54.0.0/16

The portion after the / is the subnet mask which specifies how many bits of the specified address should be examined to determine if a connection's IP address matches the rule.

In your case it's easy to figure this out. You want to match addresses based only on the first two octets (13.54.x.x) of the IP address. An octet contains 8 bits, so two octets equals 16 bits or a mask of /16.

Find out more on Wikipedia about using a mask of bits to indicate which parts of an IP are matched.

You can block/allow the IP range 13.54.0.0 to 13.54.255.255 using the /16 mask thusly:

13.54.0.0/16

###Create a Single Firewall Rule Using a Subnet Mask

You can create a single firewall rule to block the IP range 13.54.0.0 to 13.54.255.255 using the /16 mask like this:

13.54.0.0/16

The portion after the / is the subnet mask which specifies how many bits of the specified address should be examined to determine if a connection's IP address matches the rule.

In your case it's easy to figure this out. You want to match addresses based only on the first two octets (13.54.x.x) of the IP address. An octet contains 8 bits, so two octets equals 16 bits or a mask of /16.

Find out more on Wikipedia about using a mask of bits to indicate which parts of an IP are matched.