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Cisco PIX Firewall and VPN Configuration Guide
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Chapter 3 Controlling Network Access and Use
Downloading Access Lists
Statements are separated by colons (:). Statements should not include the access-list command or the
access list name. You can configure multiple occurrences of the string “ip:inacl#nnn=” in the same user
authentication profile to define a PIX
Firewall access list. If multiple entries have the same sequence
number, they will be configured in the same order as they appear in the Cisco-specific VSA attribute.
Multiple lines may be used to configure multiple elements, but an element must be completely contained
on a single line. For example, the permit tcp any any command cannot be broken into two separate
lines.
A downloadable ACL without a name is assigned a name by the PIX Firewall after it is downloaded in
the following format:
AAA-user-username
Where username is the name of the user that is being authenticated.
If an access-list command statement has a syntax or semantics error, or if the no access-list command
is used (an empty access list), Syslog messages will be generated. However, an error with a single
access-list command does not abort the processing of the entire downloaded ACL.
Example 3-6 Example Configuration for a Downloadable Access List
The following configuration would be entered for the user Admin in the [009\001] cisco-av-pair field
under Group Setup>Cisco IOS/PIX RADIUS Attributes:
ip:inacl#1=permit tcp 10.1.0.0 255.0.0.0 10.0.0.0 255.0.0.0
ip:inacl#99=deny tcp any any
ip:inacl#2=permit udp 10.1.0.0 255.0.0.0 10.0.0.0 255.0.0.0
ip:inacl#99=deny udp any any
ip:inacl#3=permit icmp 10.1.0.0 255.0.0.0 10.0.0.0 255.0.0.0
The resulting downloaded access-list commands on PIX Firewall are as follows:
access-list AAA-user-foo; 5 elements
access-list AAA-user-foo permit tcp 10.1.0.0 255.0.0.0 10.0.0.0 255.0.0.0
access-list AAA-user-foo permit udp 10.1.0.0 255.0.0.0 10.0.0.0 255.0.0.0
access-list AAA-user-foo permit icmp 10.1.0.0 255.0.0.0 10.0.0.0 255.0.0.0
access-list AAA-user-foo deny tcp any any
access-list AAA-user-foo deny udp any any
Software Restrictions
When downloading access lists via RADIUS, the following restrictions apply:
• RADIUS packet size is limited to 4096, but the actual size for the access list can vary considerably
depending on the existence of other variable-length, RADIUS attributes.
• Each RADIUS attribute field used to specify access lists is limited to 253 bytes.
Note If there exists any incompatibility between the PIX Firewall and the Cisco IOS access list, the
incompatibility will also exist for the downloaded access list. In other words, an access list defined for
PIX
Firewall on a AAA server may not be valid if the access list is downloaded to Cisco IOS software,
and vice versa.
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