Manual Chapter : Configuring Dynamic ACLs

Applies To:

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BIG-IP APM

  • 15.0.0
Manual Chapter

Configuring Dynamic ACLs

Overview: Applying ACLs from session variables

You can apply ACLs by using the dynamic ACL action in an APM access policy. Sources of dynamic ACL entries are session variables that can contain data from external servers, such as Active Directory, RADIUS, or LDAP, or internal sources.
After you configure ACLs in a supported format, you can configure a dynamic ACL action to extract and use the ACLs.

About Dynamic ACLs

A
dynamic ACL
is an ACL whose ACL entries are defined during access policy execution time, and the entries are stored and enforced for that particular Access session. The source of ACL entries is a session variable having content that can be sourced from external sources such as ActiveDirectory, LDAP, RADIUS, or internal sources such as iRules, data groups, or any combination of the above.
Access Policy Manager supports dynamic ACLs in F5 ACL format, and in a subset of the Cisco ACL format.
A dynamic ACL action includes these configuration elements and options:
Source
Specifies a type of session variable (
Custom
or
CiscoAV-PairVSA
) and the source session variable from which the dynamic ACL is derived. For
Custom
dynamic ACL entries, this is any session variable that is populated with an F5 format ACL. For
CiscoAV-PairVSA
dynamic ACL entries, this is predefined as
session.radius.last.attr.vendor-specific.1.9.1
.
ACL
Specifies the dynamic ACL container configured on the BIG-IP system. Dynamic ACL objects are empty container ACLs that you define on the system.
Format
Specifies the format (F5 or Cisco) used to define the ACL.
To succeed, a dynamic ACL action must follow actions that populate the session variables with ACLs.

Configuring a dynamic ACL container

A dynamic ACL container provides an unconfigured ACL that you select when you specify a dynamic ACL action in an access policy.
  1. On the Main tab, click
    Access
    Access Control Lists
    .
    The ACLs screen opens.
  2. Click
    Create
    .
    The New ACL screen opens.
  3. In the
    Name
    field, type a name for the access control list.
  4. From the
    Type
    list, select
    Dynamic
    .
  5. In the
    Description
    field, add a description of the access control list.
  6. From the
    ACL Order
    list, specify the order in which to add the new ACL relative to other ACLs:
    • Select
      After
      to add the ACL after a specific ACL and select the ACL from the list.
    • Select
      Specify
      to type the specific number of the ACL in the field.
    • Select
      Last
      to add the ACL at the last position in the list.
  7. From the
    Match Case for Paths
    list, select
    Yes
    to match case for paths, or
    No
    to ignore path case.
    This setting specifies whether alphabetic case is considered when matching paths in an access control entry.
  8. Click the
    Create
    button.
    The ACL Properties screen opens; it displays the newly configured dynamic ACL container.

Adding a dynamic ACL to an access policy

Before you start this task, configure an access profile and a dynamic ACL container. Add an authentication action to the access policy before the dynamic ACL action so that Access Policy Manager can first capture authentication variables that contain the dynamic ACL specification.
Configure a dynamic ACL action to extract and apply an ACL from an AAA server (Active Directory, LDAP, or RADIUS).
Because a dynamic ACL is associated with a user directory, you can use one to assign ACLs specifically per the user session.
  1. On the Main tab, click
    Access
    Profiles / Policies
    .
    The Access Profiles (Per-Session Policies) screen opens.
  2. In the Per-Session Policy column, click the
    Edit
    link for the access profile you want to configure.
    The visual policy editor opens the access policy in a separate screen.
  3. Click the
    (+)
    icon anywhere in the access policy to add a new item.
    Only an applicable subset of access policy items is available for selection in the visual policy editor for any access profile type.
    A popup screen opens, listing predefined actions on tabs such as General Purpose, Authentication, and so on.
  4. From the Assignment tab, select
    Dynamic ACL
    , and click
    Add Item
    .
    A properties screen opens.
  5. To add an ACL, click the
    Add new entry
    button.
    A new row opens in the table.
  6. Select one of these from the list:
    • Custom
      Select to use a custom ACL. The ACL source can be an attribute from an AD, RADIUS, or LDAP directory, or any properly formatted session variable.
    • Cisco AV-Pair VSA
      Select to use a Cisco AV-Pair ACL from a RADIUS directory.
  7. In the
    Source
    field, type the attribute from which the Dynamic ACL action extracts ACLs.
    If you are using Cisco AV-Pair VSA from a RADIUS server, the field is prepopulated with
    session.radius.last.attr.vendor-specific.1.9.1
    .
  8. From the
    ACL
    list, select the dynamic ACL container that you configured previously.
  9. From the
    Format
    list, select the format in which the ACL is specified.
  10. To configure another ACL, click the
    Add new entry
    button and repeat the configuration steps.
  11. Select
    Save
    to save any changes and return to the policy.
  12. Complete the policy:
    1. Add any additional policy items you require.
    2. Change the ending from
      Deny
      to
      Allow
      on any access policy branch on which you want to grant access.
  13. Click the
    Apply Access Policy
    link to apply and activate the changes to the policy.
The access policy is configured to extract an ACL from an AAA server and apply it when processing occurs on the access policy branch.
To apply this access policy to network traffic, add the access profile to a virtual server.
To ensure that logging is configured to meet your requirements, verify the log settings for the access profile.

Using dynamic ACLs with multiple dynamic ACL objects

In an access policy, you can use the Variable Assign agent before a Dynamic ACL agent having multiple dynamic ACL objects. This allows you to combine multiple objects in a dynamic ACL. Here an example shows the general steps to do this. The policy you are working with needs to have a Variable Assign agent.
  1. On the Main tab, click
    Access
    Profiles / Policies
    .
    The Access Profiles (Per-Session Policies) screen opens.
  2. In the Per-Session Policy column, click the
    Edit
    link for the access profile you want to configure.
    The visual policy editor opens the access policy in a separate screen.
  3. In the visual policy editor, create entries for session variables with the required ACL values in the Variable Assign agent. For example:
  4. On the Main tab, click
    Access
    Access Control Lists
    .
  5. Create the corresponding dynamic ACL objects in Access Control Lists. For example:
  6. In the visual policy editor, add the assigned session variable dynamic ACL values to the Dynamic ACL agent selecting the corresponding ACL in the appropriate format (Cisco or F5). For example:
  7. Add the ACL entries to the RADIUS server (here named
    apm03
    ) for the corresponding user to be applied as shown in the example.
    In this example, for the host to be allowed, you need to specify the virtual server IP address and not the pool IP address, and the log indicates the logging for the corresponding log message to appear in
    /var/log/pktfilter
    :
    test Cleartext-Password := "click123" Service-Type = Framed-User, Framed-Protocol = PPP, Framed-Filter-Id = "std.ppp", Framed-MTU = 1500, Framed-Compression = Van-Jacobsen-TCP-IP, Cisco-AVPair = "ip:inacl#1=permit tcp any host 10.192.152.109 log", Cisco-AVPair += "ip:inacl#2=deny tcp any any log"
  8. Access the virtual IP address (for example,
    http://10.192.152.109
    ) and upon entering the credentials
    test/click123
    , a message box displaying
    Dynamic ACL is assigned
    appears.
  9. On the BIG-IP system 10.192.34.121 command line, typing
    sessiondump –allkeys
    shows the following values for
    session.assigned.dacls
    :
    cdc9d4e5.session.assigned.dacl./Common/radius_apm03_dacl 65 { allow log tcp any 10.192.152.109 } { discard log tcp any any } cdc9d4e5.session.assigned.dacl./Common/variable_assign_ghi 26 { allow tcp any 1.2.3.4 } cdc9d4e5.session.assigned.dacl./Common/variable_assign_abc 26 { allow tcp any 1.2.3.5 } cdc9d4e5.session.assigned.dacl./Common/variable_assign_def 26 { allow tcp any 1.2.3.6 } cdc9d4e5.session.assigned.dacls 112 /Common/radius_apm03_dacl /Common/variable_assign_ghi /Common/variable_assign_abc /Common/variable_assign_def cdc9d4e5.session.radius. /Common/ap-radius-dacl-test_act_radius_auth_ag.attr. vendor-specific.1.9.1 83 ip:inacl#1=permit tcp any host 10.192.152.109 log | ip:inacl#2=deny tcp any any log
  10. When you click
    Continue
    in the
    Dynamic ACL is assigned
    message box, the pool IP address (10.192.254.11:80) with the test php page opens. The following log entry in
    /var/log/pktfilter
    shows the allowed ACL:
    Nov 9 10:17:40 bigip4002mgmt notice tmm[32697]: 01580005:5: /Common/ap-radius-dacl-test:Common:cdc9d4e5: allow ACL: /Common/radius_apmdev03_dacl@cdc9d4e5:0 packet:http://10.192.152.109/ tcp 192.168.85.53:59888 -> 10.192.152.109:80

F5 ACL format

Specifies F5 ACL syntax and provides examples. This syntax applies to both static and dynamic ACLs.
Specify an F5 ACL using this syntax.
comment { action [logging_options] context } comment { action [logging_options] context }...
The syntax allows multiple ACLs in a single string along with comments.

comment

Any characters before an open curly brace ({) or after a closed curly brace (}) are treated as comments. Comments are optional. They have no effect on the ACLs. These examples show identical ACLs with different comments; APM interprets them as being the same.
String comments
This is my HTTP server ACL { allow tcp any 1.2.3.4:80 } This is my default ACL { reject ip any any }
A space as a comment
{ allow tcp any 1.2.3.4:80 } { reject ip any any }
Newline comments
{ allow tcp any 1.2.3.4:80 }\n
{ reject ip any any }\n
Vertical bar comments
| { allow tcp any 1.2.3.4:80 } | { reject ip any any } |

action

This is an action that the ACL takes on traffic that matches the ACL context.
allow
Allows the specified traffic.
reject
Rejects the specified traffic and sends a TCP RST code to the initiator.
discard
Silently drops the packets.
continue
Skips checking against the remaining access control entries in this ACL, and continues evaluation at the next ACL.

logging_options

Specifying a logging option is optional.
log
Enables default logging for the ACL
log-packet
Writes packet-level logs to the packet filter log file
log-verbose
Writes verbose logs
log-summary
Writes summary logs
log-config
Writes configuration logs to the configuration log file

context

Context specifies a protocol followed by addresses, networks, and ports for the ACL action.
http
HTTP protocol traffic. Requires that you specify an HTTP or HTTPS URL in the ACL definition
udp
UDP traffic only
tcp
TCP traffic only
ip
IP protocol traffic
F5 ACL format treats IP protocol number zero (0) as a wildcard, meaning that it applies to all IPv4 and IPv6 traffic.
For example,
{ reject ip 0 any any }
is the equivalent of
{ reject ip any any }
.

Address, network, and port specification

Specify addresses in a pair separated by a space. The first address in the pair should match the host, and the second address in the pair should match the destination. This syntax:
any[/mask][:port]
matches any host or IP address with an optional subnet mask or a port. For example,
{ allow tcp any 1.2.3.4 }
allows TCP traffic between any host and the destination IP address 1.2.3.4.
{ allow tcp any/8 1.2.3.4 }
allows TCP traffic between any host within the subnet 255.0.0.0 and the destination IP address 1.2.3.4.
{ allow tcp any/8:8000 1.2.3.4 }
allows TCP traffic between any host within the subnet 255.0.0.0 on port 8000 and the destination IP address 1.2.3.4.
This syntax:
IP address[/mask][:port]
matches a specific IP address with an optional subnet mask or a port. For example,
{ allow tcp 1.1.1.1 1.2.3.4 }
allows TCP traffic between the host IP address 1.1.1.1 and the destination IP address 1.2.3.4.
{ allow tcp 1.1.1.1:22 1.2.3.4 }
allows TCP traffic between the host IP address 1.1.1.1 on port 22 and the destination IP address 1.2.3.4.
F5 ACL with the IP protocol
This example shows how to specify an IP protocol address in F5 ACL format. An IP protocol number, 51, and an address pair specification follow the context word
ip
.
{ allow ip 51 any 1.2.3.4 }
F5 ACL with the TCP or UDP protocol
This example shows how to specify a TCP or UDP protocol address in F5 ACL format. An address pair specification follows the context word (
tcp
or
udp)
.
{ allow tcp any 1.2.3.4 } { allow udp any 1.2.3.4 }
F5 ACL with the HTTP protocol
These examples show how to specify an HTTP protocol address in F5 ACL format. A host address, destination address, and URL follow the context word 
http
. The URL specification supports wildcards with glob matching.
{ allow http any 1.2.3.4 https://www.siterequest.com/* } { allow http any 1.2.3.0/24 http://*.siterequest.com/* } { allow http any 1.2.3.0/24 http://*.siterequest.???/* }

Cisco ACL format

Specifies the subset of Cisco ACL syntax that Access Policy Manager supports and provides examples.

Usage

On a RADIUS server, Access Policy Manager supports dynamic ACLs that use the subset of the Cisco ACL format described here.

Prefix

You must specify a prefix. For IPv4, use
ip:inacl#
X
=
where 
X
 is an integer used as a rule identifier. For IPv6, use
ipv6:inacl#
X
=
.

Keywords

These keywords are mapped with the F5 log-packet format:
log
 and 
log-input
.
These keywords are not supported: 
tos
established
time-range
,
 dynamic
, and 
precedence
.

Supported specification for Cisco ACL for IP protocol

{
ip
|
ipv6
}
:inacl#
X
={
deny
|
permit
} {
ip
|
ipv6
}
source
source-wildcard
destination
destination-wildcard
[
log
|
log-input
]
For example:
ipv6:inacl#10=permit ipv6 any any log

Supported specification for Cisco ACL for TCP protocol

{
ip
|
ipv6
}
:inacl#
X
={
deny
|
permit
}
tcp
source
source-wildcard
[operator [port]]
destination
destination-wildcard
[operator [port]]
[
log
|
log-input
]
For example:
ip:inacl#10=permit tcp any host 10.168.12.100 log

Supported specification for Cisco ACL for UDP protocol

{
ip
|
ipv6
}
:inacl#
X
={
deny
|
permit
}
udp
source
source-wildcard
[operator [port]]
destination
destination-wildcard
[operator [port]]
[
log
|
log-input
]
For example:
ip:inacl#2=deny udp any any log