Brocade Virtual ADX Security Guide (Supporting ADX v03.1.00) - Manual (Page 51)

Brocade Virtual ADX Security Guide 39
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Modifying ACLs
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To show all entries containing the keyword “deny” you obtain the following
output:
Virtual ADX (config)#show access-list 99 | include deny
Standard IP access-list 99
ACL Remark: Deny Building A
deny host 10.2.3.4
deny host 10.10.11.12
NOTE
All lines with the keyword “deny”, including remarks are included in the display.
Modifying ACLs
When you use the Brocade Virtual ADX device’s CLI to configure any ACL, the software places the
ACL entries in the ACL in the order you enter them. For example, if you enter the following entries in
the order shown below, the software always applies the entries to traffic in the same order.
Virtual ADX (config)#access-list 1 deny 10.157.22.0/24
Virtual ADX (config)#access-list 1 permit 10.157.22.26
If a packet matches the first ACL entry in this ACL and is therefore denied, the software does not
compare the packet to the remaining ACL entries. In this example, packets from host 10.157.22.26
will always be dropped, even though packets from this host match the second entry.
You can use the CLI to reorder entries within an ACL by individually removing the ACL entries and
then re-adding them. To use this method, enter “no” followed by the command for an ACL entry,
and repeat this for each ACL entry in the ACL you want to edit. After removing all the ACL entries
from the ACL, re-add them.
This method works well for small ACLs such as the example above, but can be impractical for ACLs
containing many entries. Therefore, Brocade Virtual ADX devices provide an alternative method.
The alternative method lets you upload an ACL list from a TFTP server and replace the ACLs in the
device running-config file with the uploaded list. Thus, to change an ACL, you can edit the ACL on
the file server, then upload the edited ACL to the device. You then can save the changed ACL to the
device’s startup-config file.
ACL lists contain only the ACL entries themselves, not the assignments of ACLs to interfaces. You
must assign the ACLs on the device itself.
NOTE
The only valid commands that are valid in the ACL list are the access-list and end commands. The
Brocade Virtual ADX device ignores other commands in the file.
To modify an ACL by configuring an ACL list on a file server.
1. Use a text editor to create a new text file. When you name the file, use 8.3 format (up to eight
characters in the name and up to three characters in the extension).
NOTE
Make sure the Brocade Virtual ADX device has network access to the TFTP server.
2. Optionally, clear the ACL entries from the ACLs you are changing by placing commands such as
the following at the top of the file.