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Default Setting
None
Command Mode
Standard IPv4 ACL
Command Usage
• New rules are appended to the end of the list.
• Address bitmasks are similar to a subnet mask, containing four integers from
0 to 255, each separated by a period. The binary mask uses 1 bits to indicate
“match” and 0 bits to indicate “ignore.” The bitmask is bitwise ANDed with the
specified source IP address, and then compared with the address for each IP
packet entering the port(s) to which this ACL has been assigned.
Example
This example configures one permit rule for the specific address 10.1.1.21 and
another rule for the address range 168.92.16.x – 168.92.31.x using a bitmask.
Console(config-std-acl)#permit host 10.1.1.21
Console(config-std-acl)#permit 168.92.16.0 255.255.240.0
Console(config-std-acl)#
Related Commands
access-list ip (26-2)
permit, deny (Extended IPv4 ACL)
This command adds a rule to an Extended IPv4 ACL. The rule sets a filter condition
for packets with specific source or destination IP addresses, protocol types, source
or destination protocol ports, or TCP control codes. Use the
no
form to remove a
rule.
Syntax
[no] {permit | deny} [protocol-number | udp]
{any | source address-bitmask | host source}
{any | destination address-bitmask | host destination}
[precedence precedence] [tos tos] [dscp dscp]
[
source-port
sport [bitmask]] [
destination-port
dport [port-bitmask]]
[no] {permit | deny} tcp
{any | source address-bitmask | host source}
{any | destination address-bitmask | host destination}
[precedence precedence] [tos tos] [dscp dscp]
[
source-port
sport [bitmask]] [
destination-port
dport [port-bitmask]]
[
control-flag
control-flags flag-bitmask]
• protocol-number – A specific protocol number. (Range: 0-255)
• source – Source IP address.
• destination – Destination IP address.
• address-bitmask – Decimal number representing the address bits to match.
26-3
IPv4 ACLs
26