Home Theater Server User Manual

ServerIron ADX Security Guide 59
53-1002440-03
Configuring numbered and named ACLs
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The <num> parameter indicates the ACL number and be from 100 – 199 for an extended ACL.
The deny | permit parameter indicates whether packets that match the policy are dropped or
forwarded.
The <ip-protocol> parameter indicates the type of IP packet you are filtering. You can specify a
well-known name for any protocol whose number is less than 255. For other protocols, you must
enter the number. Enter “?” instead of a protocol to list the well-known names recognized by the
CLI.
The <source-ip> | <hostname> parameter specifies the source IP host for the policy. If you want
the policy to match on all source addresses, enter any.
The <wildcard> parameter specifies the portion of the source IP host address to match against.
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 Classless Interdomain Routing (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 zeros. 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 <destination-ip> | <hostname> parameter specifies the destination IP host for the policy. If
you want the policy to match on all destination addresses, enter any.
The <icmp-type> | <icmp-num> parameter specifies the ICMP protocol type.
• This parameter applies only if you specified icmp as the <ip-protocol> value.
• If you use this parameter, the ACL entry is sent to the CPU for processing.
• If you do not specify a message type, the ACL applies to all types of ICMP messages.
The <icmp-num> parameter can be a value from 0 – 255.
The <icmp-type> parameter can have one of the following values, depending on the software
version the device is running:
• any-icmp-type
• echo