Brocade Communications Systems ServerIron ADX 12.4.00a - Manual (Page 70)

56 ServerIron ADX Security Guide
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Configuring numbered and named ACLs
2
The <wildcard> parameter specifies the mask value to compare against the host address specified
by the <source-ip> parameter. The <wildcard> is a four-part value in dotted-decimal notation (IP
address format) consisting of ones and zeros. Zeros in the mask mean the packet’s source address
must match the <source-ip>. Ones mean any value matches. For example, the <source-ip> and
<wildcard> values 209.157.22.26 0.0.0.255 mean that all hosts in the Class C sub-net
209.157.22.x match the policy.
If you prefer to specify the wildcard (mask value) in CIDR format, you can enter a forward slash after
the IP address, then enter the number of significant bits in the mask. For example, you can enter
the CIDR equivalent of “209.157.22.26 0.0.0.255” as “209.157.22.26/24”. The CLI automatically
converts the CIDR number into the appropriate ACL mask (where zeros instead of ones are the
significant bits) and changes the non-significant portion of the IP address into ones. For example, if
you specify 209.157.22.26/24 or 209.157.22.26 0.0.0.255, then save the changes to the
startup-config file, the value appears as 209.157.22.0/24 (if you have enabled display of sub-net
lengths) or 209.157.22.0 0.0.0.255 in the startup-config file.
If you enable the software to display IP sub-net masks in CIDR format, the mask is saved in the file
in
“/<mask-bits>” format. To enable the software to display the CIDR masks, enter the ip
show-subnet-length command at the global CONFIG level of the CLI. You can use the CIDR format to
configure the ACL entry regardless of whether the software is configured to display the masks in
CIDR format.
NOTE
If you use the CIDR format, the ACL entries appear in this format in the running-config and
startup-config files, but are shown with sub-net mask in the display produced by the show ip
access-list command.
The host <source-ip> | <hostname> parameter lets you specify a host IP address or name. When
you use this parameter, you do not need to specify the mask. A mask of all zeros (0.0.0.0) is
implied.
The any parameter configures the policy to match on all host addresses.
The in | out parameter specifies whether the ACL applies to incoming traffic or outgoing traffic on
the interface to which you apply the ACL. You can apply the ACL to an Ethernet port. Note that the
out option is not supported in the rule-based ACL mode.
Configuring extended numbered ACLs
This section describes how to configure extended numbered ACLs:
• For configuration information on named ACLs, refer to “Configuring numbered and named
ACLs” on page 54.
• For configuration information on standard ACLs, refer to “Configuring standard numbered
ACLs” on page 55.
Extended ACLs let you permit or deny packets based on the following information:
• IP protocol
• Source IP address or host name
• Destination IP address or host name
• Source TCP or UDP port (if the IP protocol is TCP or UDP)
• Destination TCP or UDP port (if the IP protocol is TCP or UDP)