- Finding Feature Information
- Restrictions for Flexible Packet Matching
- Information About Flexible Packet Matching
- Flexible Packet Matching Functional Overview
- Traffic Classification Definition Files for the Flexible Packet Matching XML Configuration
- FPM on the Catalyst 6500 Equipped with PISA Overview
- Encrypted TCDF Support
- TCDF Packaging Support
- Full Packet FPM Search Window Increase
- Session-based Flexible Packet Matching
- How to Configure a Flexible Packet Matching Traffic Class and Traffic Policy
- Configuration Examples for Flexible Packet Matching
- Example: Configuring FPM for Slammer Packets
- Example: Configuring FPM for Blaster Packets
- Example: Configuring FPM for MyDoom Packets
- Example: Configuring and Verifying FPM on ASR Platform
- Example: Configuring Session-based FPM
- Example: Configuring Session-based FPM with a Filter for Increased Performance and Accuracy
- Example: Verifying FPM Package Support
- Additional References
- Feature Information for Flexible Packet Matching
Flexible Packet Matching
Flexible Packet Matching (FPM) is an access control list (ACL) pattern matching tool, providing more thorough and customized packet filters. FPM enables users to match on arbitrary bits of a packet at an arbitrary depth in the packet header and payload. FPM removes constraints to specific fields that had limited packet inspection.
FPM enables users to create their own stateless packet classification criteria and to define policies with multiple actions (such as drop, log, or send Internet Control Message Protocol [ICMP] unreachable1) to immediately block new viruses, worms, and attacks.
- Finding Feature Information
- Restrictions for Flexible Packet Matching
- Information About Flexible Packet Matching
- How to Configure a Flexible Packet Matching Traffic Class and Traffic Policy
- Configuration Examples for Flexible Packet Matching
- Additional References
- Feature Information for Flexible Packet Matching
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Restrictions for Flexible Packet Matching
- In Cisco IOS Release 12.4(4)T, FPM is available only in advanced security images.
- In Cisco IOS Release 12.2(18)ZY, FPM is available in ipbase and ipservices images for the Supervisor Engine 32 Programmable Intelligent Services Accelerator (PISA) platform.
- Although access to an XML editor is not required, XML will ease the creation of protocol header description files (PHDFs).
- FPM cannot be used to mitigate an attack that requires stateful classification.
- Because FPM is stateless, it cannot keep track of port numbers being used by protocols that dynamically negotiate ports. Thus port numbers must be explicitly specified when using FPM.
- FPM cannot perform IP fragmentation or TCP flow reassembly.
- FPM inspects only IPv4 unicast packets.
- FPM cannot classify packets with IP options.
- FPM does not support multicast packet inspection.
- FPM is not supported on tunnel and Multiprotocol Label Switching (MPLS) interfaces.
- FPM cannot be configured on FlexWAN cards.
- Noninitial fragments will not be matched by the FPM engine.
- Offset can be a constant only in a match start construct.
- FPM cannot match across packets.
- Mapping of FPM policies to the control plane is not supported.
Information About Flexible Packet Matching
- Flexible Packet Matching Functional Overview
- Traffic Classification Definition Files for the Flexible Packet Matching XML Configuration
- FPM on the Catalyst 6500 Equipped with PISA Overview
- Encrypted TCDF Support
- TCDF Packaging Support
- Full Packet FPM Search Window Increase
- Session-based Flexible Packet Matching
Flexible Packet Matching Functional Overview
FPM allows customers to create their own filtering policies that can immediately detect and block new viruses and attacks.
A filtering policy is defined via the following tasks:
- Load a PHDF (for protocol header field matching)
- Define a class map and define the protocol stack chain (traffic class)
- Define a service policy (traffic policy)
- Apply the service policy to an interface
Protocol Header Description File
Protocol headers are defined in separate files called PHDFs; the field names that are defined within the PHDFs are used for defining the packet filters. A PHDF is a file that allows the user to leverage the flexibility of XML to describe almost any protocol header. The important components of the PHDF are the version, the XML file schema location, and the protocol field definitions. The protocol field definitions name the appropriate field in the protocol header, allow for a comment describing the field, provide the location of the protocol header field in the header (the offset is relative to the start of the protocol header), and provide the length of the field. Users can choose to specify the measurement in bytes or in bits.
 Note |
The total length of the header must be specified at the end of each PHDF. |
Note |
When redundant sup PHDF files are used by the FPM policy, the files should also be on the standby sup's corresponding disk. If the files are not available the FPM policy will not work after the switchover. |
Users can write their own custom PHDFs via XML for existing or proprietary protocols. However, the following standard PHDFs can also be loaded onto the router via the load protocol command: ether.phdf, ip.phdf, tcp.phdf, and udp.phdf.
Note |
Because PHDFs are defined via XML, they are not shown in a running configuration. However, you can use the show protocol phdf command to verify the loaded PHDF. |
Standard PHDFs are available on Cisco.com at the following URL: http://www.cisco.com/cgi-bin/tablebuild.pl/fpm
Filter Description
A filter description is a definition of a traffic class that can contain the header fields defined in a PHDF (using the match field command). If a PHDF is not loaded, the traffic class can be defined through the datagram header start (Layer 2) or the network header start (Layer 3) (using the match start command). If a PHDF has been loaded onto the router, the class specification begins with a list of the protocol headers in the packet.
A filter definition also includes the policy map; that is, after a class map has been defined, a policy map is needed to bind the match to an action. A policy map is an ordered set of classes and associated actions, such as drop, log, or send ICMP unreachable.
For information on how to configure a class map and a policy map for FPM, see the How to Configure a Flexible Packet Matching Traffic Class and Traffic Policy section.
Traffic Classification Definition Files for the Flexible Packet Matching XML Configuration
FPM uses a traffic classification definition file (TCDF) to define policies that can block attacks on the network. Before Cisco IOS Release 12.4(6)T, FPM defined traffic classes (class maps), policies (policy maps), and service policies (attach policy maps to class maps) through the use of the command line interface (CLI). With TCDFs, FPM can use XML as an alternative to the CLI to define classes of traffic and specify actions to apply to the traffic classes. Traffic classification behavior is the same whether you create the behavior using a TCDF or configure it using CLI commands. Once a TCDF is created, it can be loaded on any FPM-enabled device in the network.
Note |
TCDFs are supported only in Cisco IOS Release 12.4(6)T and later T-train releases. |
For more information on configuring FPM using TCDFs, see "Flexible Packet Matching XML Configuration".
FPM on the Catalyst 6500 Equipped with PISA Overview
The PISA functions as a network processor-based daughter card that is mounted on the Catalyst 6500 Supervisor. PISA provides a superset of the multilater switch feature card 2a (MSFC2a) capabilities. In addition to performing all of the same functions as the MSFC2a, PISA provides dedicated hardware to accelerate certain features such as FPM.
Network-Based Application Recognition (NBAR) occurs before FPM; thus, packets that are dropped by FPM are processed by NBAR.
Logging FPM Activity
In software-based FPM logging, every flow is logged and aggregated statistics are provided for each flow. Logging every flow for FPM on PISA would overwhelm the CPU; thus, only selective packets are logged. That is, when a packet matches a policy that is to be logged or the first time, the packet is logged, time-stamped, and stored. For every subsequent packet that matches any policy with a log action, the packet is checked for the difference between the current time (which is clocked by the global timer) and the last time stamp. If the current time is later than the last time stamp, the packet is logged and the "stamp time" is updated with the current time.
Memory Requirements
Note |
Because memory requirements vary among system configurations, the requirements listed in this document are estimates. |
- PISA will support a maximum of 1024 interfaces; however, it is expected that no more than 256 interfaces will be configured with FPM.
- A maximum of 32 classes per policy map, and a total of 1024 classes globally, are supported.
- A maximum of 32 filters (such as match entries) per class map are supported. (However, some optimizations for better performance are possible with match-any type of class maps that have filters starting at the same offset and the same size.)
Encrypted TCDF Support
TCDFs provide preconfigured FPM filters written in XML format that can be directly loaded onto a router. The XML format prohibits the Cisco Product Security Incident Response Team (PSIRT) from being able to provide public TCDF filters because it would expose the vulnerability to potential attackers. This information could then be used to exploit PSIRT vulnerabilities in some systems.
FPM encrypted TCDF (eTCDF) filter support will provide encrypted FPM filters. Applying the PSIRT provided eTCDF FPM filter will protect routers from PSIRT incidents, allowing time to certify new Cisco IOS releases that contains the PSIRT fixes.
To enter FPM match encryption filter configuration mode, use the match encrypted command in class-map configuration mode. This mode enables you to enter encrypted filter-related information like the cipher key cipher value, and filter hash.
Note |
The encrypted filter contents are not stored in the class map until the exit or endcommandis entered. When you exit from the encrypted filter submode without entering all the mandatory parameters, an error message is printed before exiting the submode. The cipher key, cipher value, and filter hash are the mandatory values. A filter is not configured in this case. |
TCDF Packaging Support
TCDFs are FPM filters in XML format. Each TCDF file is designed to filter for a single individual worm or virus. TCDF packaging support provides packages containing at least one or more worm or virus filters and efficiently updates FPM filters as threat characteristics change. When FPM filters are updated, all systems in a network are automatically updated. This behavior reduces the amount of router configuration needed to deploy FRM filters.
To access TCDF packages, configure the router using the time-range command to periodically check for package updates. At the specified time, the router connects to the server containing the FPM packages to request the latest version. When the router gets feedback from the server, it compares the FPM package version number from the server with the local FPM package version. If there is an updated package on the server, then the router downloads the package content, replaces the old package with the new package, and updates the local configuration.
Full Packet FPM Search Window Increase
FPM supports searching for patterns up to 256 bytes long anywhere within the entire packet. Also, the number of filters that can be configured per class map is 32. The additional filters can help offset adverse CPU performance that may occur if the "window" for pattern searching is increased. This will also allow FPM users to take advantage of the regular expressions (regex) strings used by Intrusion Prevention Systems (IPS) in their signatures.
Session-based Flexible Packet Matching
FPM works at its best when the filter information exists in all packets of a packet flow. However, if matching contents only exist in a limited number of packets (regex strings and strings in the payload), then FPM can only apply actions to these packets, and miss the other packets in the same packet flow, which are a sequence of packets with the same attributes.
With the introduction of Cisco IOS Release 15.1(3)T, FPM can now match every packet against the filters specified in the class map and pass the match result to consecutive packets of the same network session. If a filter matches with malicious content in the packet's protocol header or payload, then the required action is taken to resolve the problem.
The match class session command configures match criteria that identify a session containing packets of interest, which is then applied to all packets transmitted during the session. The packet-range and byte-range keywords are used to create a filter mechanism that increases the performance and matching accuracy of regex-based FPM class maps by classifying traffic that resides in the narrow packet number or byte ranges of each packet flow. If packets go beyond the classification window, then the packet flow can be identified as unknown and packet classification is terminated early to increase performance. For example, a specific application can be blocked efficiently by filtering all packets that belong to this application on a session. These packets are dropped without matching every individual packet with the filters, which improves the performance of a session.
These filters also reduce the number of false positives introduced by general regex-based approaches. For example, internet company messenger traffic can be classified with a string like intco, intcomsg, and ic. These strings are searched for in a packet's payload. These small strings can appear in the packet payload of any other applications, such as e-mail, and can introduce false positives. False positives can be avoided by specifying which regex is searched within which packet of a particular packet flow. See "Creating a Traffic Class for Flexible Packet Matching" for more information.
Once the match criteria are applied to packets belonging to the specific traffic class, these packets can be discarded by configuring the drop allcommand in a policy map. Packets match only on the packet flow entry of an FPM, and skip user-configured classification filters. See "Creating a Traffic Policy for Flexible Packet Matching" for more information.
A match class does not have to be applied exclusively for a regex-based filter. Any FPM filter can be used in the nested match class filter. For example, if the match class c1 has the filter match field TCP source-port eq 80, then the match class c1 session command takes the same action for the packets that follow the first matching packet.
How to Configure a Flexible Packet Matching Traffic Class and Traffic Policy
- Creating a Traffic Class for Flexible Packet Matching
- Creating a Traffic Policy for Flexible Packet Matching
- Configuring Packaging Support for Flexible Packet Matching
- Configuring eTCDF Through the Command-Line Interface
Creating a Traffic Class for Flexible Packet Matching
Note |
If the PHDF protocol fields are referenced in the access-control classmap, the stack classmap is required in order to make FPM work properly |
DETAILED STEPS
Creating a Traffic Policy for Flexible Packet Matching
DETAILED STEPS
| Command or Action | Purpose | |||
|---|---|---|---|---|
|
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Example: Router> enable |
Enables privileged EXEC mode. |
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Example: Router# configure terminal |
Enters global configuration mode. |
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Example: Router(config)# policy-map type access-control fpm-udp-policy |
Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy, and enters policy-map configuration mode. |
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|
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Example: Router(config-pmap)# description "policy for UDP based attacks" |
(Optional) Adds a description to the policy map. |
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|
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Example: Router(config-pmap)# class slammer |
Specifies the name of a predefined traffic class, which was configured with the class-map command. The class command also classifies traffic to the traffic policy and enters policy-map class configuration mode. |
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|
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Example: Router(config-pmap-c)# drop all |
(Optional) Configures a traffic class to discard packets belonging to a specific class. The all keyword is used to discard the entire stream of packets belonging to the traffic class. If this command is issued, note the following restrictions:
|
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|
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Example: Router(config-pmap-c)# log all |
(Optional) Generates log messages for the traffic class. The all keyword is used to log the entire stream of discarded packets belonging to the traffic class. This keyword is only available for a class map that is created with the class-map type access-control command. |
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|
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Example: Router(config-pmap-c)# service policy fpm-udp-policy |
Creates hierarchical service policies. |
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Example: Router(config-pmap-c)# exit Example: Router(config-pmap)# exit |
Exits policy-map class configuration mode and policy-map configuration mode. |
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Example: Router(config)# interface gigabitEthernet 0/1 |
Configures an interface type and enters interface configuration mode. |
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|
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Example: Router(config-if)# service-policy type access-control input fpm-policy |
Specifies the type and the name of the traffic policy to be attached to the input or output direction of an interface. |
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Example: Router(config-if)# exit |
Exits interface configuration mode. |
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|
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Example: Router(config)# exit |
Exits global configuration mode. |
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Example: Router# show policy-map type access-control interface gigabitethernet 0/1 |
(Optional) Verifies the FPM configuration.
|
- Copying a Matched Packet To a Different Destination Interface
- Redirecting a Matched Packet To a Different Destination Interface
Copying a Matched Packet To a Different Destination Interface
Perform this task to configure a traffic class to copy packets belonging to a specific class to a different destination interface.
DETAILED STEPS
| Command or Action | Purpose | |
|---|---|---|
|
|
Example: Router> enable |
Enables privileged EXEC mode.
|
|
|
Example: Router# configure terminal |
Enters global configuration mode. |
|
|
Example: Router(config)# policy-map type access-control fpm-udp-policy |
Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy and enters policy-map configuration mode. |
|
|
Example: Router(config-pmap)# description "policy for UDP based attacks" |
(Optional) Adds a description to the policy map. |
|
|
Example: Router(config-pmap)# class cmtest |
Specifies the name of a predefined traffic class, which was configured with the class-map command, used to classify traffic to the traffic policy.
|
|
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Example: Router(config-pmap-c)# copy interface FastEthernet 4/15 |
(Optional) Configures a traffic class to copy packets belonging to a specific class to a different destination interface. If this command is issued, note the following restrictions:
|
|
|
Example: Router(config-pmap-c)# service policy fpm-udp-policy |
Creates hierarchical service policies. |
|
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Example: Router(config-pmap-c)# exit Example: Router(config-pmap)# exit |
Exits policy-map class configuration mode and policy-map configuration mode. |
|
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Example: Router(config)# interface gigabitEthernet 0/1 |
Configures an interface type and enters interface configuration mode. |
|
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Example: Router(config-if)# service-policy type access-control input fpm-policy |
Specifies the type and the name of the traffic policy to be attached to the input or output direction of an interface. |
|
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Example: Router(config-if)# exit |
Exits interface configuration mode. |
|
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Example: Router(config)# exit |
Exits global configuration mode. |
|
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Example: Router# show policy-map type access-control interface gigabit 0/1 |
(Optional) Verifies the FPM configuration. |
Redirecting a Matched Packet To a Different Destination Interface
Perform this task to configure a traffic class to redirect packets belonging to a specific class to a different destination.
DETAILED STEPS
| Command or Action | Purpose | |
|---|---|---|
|
|
Example: Router> enable |
Enables privileged EXEC mode.
|
|
|
Example: Router# configure terminal |
Enters global configuration mode. |
|
|
Example: Router(config)# policy-map type access-control fpm-udp policy |
Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy and enters policy-map configuration mode. |
|
|
Example: Router(config-pmap)# description "policy for UDP based attacks" |
(Optional) Adds a description to the policy map. |
|
|
Example: Router(config-pmap)# class cmtest |
Specifies the name of a predefined traffic class, which was configured with the class-map command, used to classify traffic to the traffic policy.
|
|
|
Example: Router(config-pmap-c)# redirect interface FastEthernet 4/15 |
(Optional) Configures a traffic class to redirect packets belonging to a specific class to a different destination interface. If this command is issued, note the following restrictions:
|
|
|
Example: Router(config-pmap-c)# service policy fpm-udp-policy |
Creates hierarchical service policies. |
|
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Example: Router(config-pmap-c)# exit Example: Router(config-pmap)# exit |
Exits policy-map class configuration mode and policy-map configuration mode. |
|
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Example: Router(config)# interface gigabitEthernet 0/1 |
Configures an interface type and enters interface configuration mode. |
|
|
Example: Router(config-if)# service-policy type access-control input fpm-policy |
Specifies the type and the name of the traffic policy to be attached to the input or output direction of an interface. |
|
|
Example: Router(config-if)# exit |
Exits interface configuration mode. |
|
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Example: Router(config)# exit |
Exits global configuration mode. |
|
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Example: Router# show policy-map type access-control interface gigabit 0/1 |
(Optional) Verifies the FPM configuration. |
Configuring Packaging Support for Flexible Packet Matching
Perform this task to configure FPM packaging support.
DETAILED STEPS
| Command or Action | Purpose | |
|---|---|---|
|
|
Example: Router> enable |
Enables privileged EXEC mode.
|
|
|
Example: Router# configure terminal |
Enters global configuration mode. |
|
|
Example: Router(config)# fpm package-info |
Enters FPM configuration mode. |
|
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Example: Router(config-fpm-pak-info)# time-range weekly |
Specifies the time interval to check for new FPM packages. |
|
|
Example: Router(config-fpm-pak-info)# host 10.0.0.1 |
Specifies the location from where FPM package updates are downloaded. |
|
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Example: Router(config-fpm-pak-info)# local-path flash: |
Specifies where the FPM packages are stored locally. |
|
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Example: Router(config-fpm-pak-info)# remote-path fpm-security |
Specifies the location of the FPM packages on the FPM server. |
|
|
Example: Router(config-fpm-pak-info)# exit |
Exits FPM configuration. |
|
|
Example: Router(config)# fpm package-group fpm-update |
Specifies an FPM group and enters FPM group definition mode. |
|
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Example: Router(config-fpm-pak-grp)# package fpm-group-44 |
Specifies an FPM package and enters FPM package definition mode. |
|
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Example: Router(config-fpm-pak-grp-pak)# action log |
Enables logging for this FPM package. |
|
|
Example: Router(config-fpm-pak-grp-pak)# exit |
Exits FPM package mode and enters FPM group definition configuration mode. |
|
|
Example: Router(config-fpm-pak-grp)# auto-load |
Enable automatic loading of the FPM package. |
|
|
Example: Router(config-fpm-pak-grp)# end |
Exits FPM configuration mode and enters privileged EXEC mode. |
Configuring eTCDF Through the Command-Line Interface
If you have access to an encrypted traffic classification definition file (eTCDF) or if you know valid values to configure encrypted FPM filters, you can configure the same eTCDF through the command-line interface instead of using the preferred method of loading the eTCDF on the router. You can copy the values from the eTCDF by opening the eTCDF in any text editor.
Perform this task to configure eTCDF through the command-line interface.
DETAILED STEPS
| Command or Action | Purpose | |
|---|---|---|
|
|
Example: Router> enable |
Enables privileged EXEC mode.
|
|
|
Example: Router# configure terminal |
Enters global configuration mode. |
|
|
Example: Router(config)# class-map type access-control match-all class1 |
Creates a class map to be used for matching packets to a specified class and enters class-map configuration mode. |
|
|
Example: Router(config-cmap)# match encrypted |
Configures the match criteria for a class map on the basis of encrypted Flexible Packet Matching (FPM) filters and enters the FPM match encryption filter configuration mode. |
|
|
Example: Router(c-map-match-enc-config)# algorithm aes256cbc |
Specifies the algorithm to be used for decrypting the filters. |
|
|
Example: Router(c-map-match-enc-config)# cipherkey realm-abc.sym |
Specifies the symmetric key-name that is used to decrypt the filter. |
|
|
Example: Router(c-map-match-enc-config)# ciphervalue #2bcXhFL8Ld1v+DqU+dnxgmONCxl4JrYfcLl95xg Example: ET0b2B1z0sjoCkozE8YxiH/SXL+eG2wf3ogaA7/Fh Example: awIH7OF3tUcS5Jwim/u95Xlzh2RLNw819tuIBCdorV Example: Cu0ZzWCF3vqwpGQzaxtSE4sFgPAvSE2LxZc/VT22 Example: F7EQKBhRo=# |
Specifies the encrypted filter contents. |
|
|
Example: Router(c-map-match-enc-config)# filter-hash AABBCCDD11223344 |
Specifies the hash for verification and validation of decrypted contents. |
|
|
Example: Router(c-map-match-enc-config)# filter-id id2 |
Specifies a filter-level ID for encrypted filters. |
|
|
Example: Router(c-map-match-enc-config)# filter-version v1 |
Specifies the filter-level version value for the encrypted filter. |
|
|
Example: Router(c-map-match-enc-config)# end |
Exits FPM match encryption filter configuration mode and returns to privileged EXEC mode. |
Configuration Examples for Flexible Packet Matching
- Example: Configuring FPM for Slammer Packets
- Example: Configuring FPM for Blaster Packets
- Example: Configuring FPM for MyDoom Packets
- Example: Configuring and Verifying FPM on ASR Platform
- Example: Configuring Session-based FPM
- Example: Configuring Session-based FPM with a Filter for Increased Performance and Accuracy
- Example: Verifying FPM Package Support
Example: Configuring FPM for Slammer Packets
The following example shows how to define FPM traffic classes for slammer packets (UDP port 1434). The match criteria defined within the class maps is for slammer packets with an IP length not to exceed 404 bytes, UDP port 1434, and pattern 0x4011010 at 224 bytes from start of IP header. This example also shows how to define the service policy "fpm-policy" and apply it to the Gigabit Ethernet interface. Show commands have been issued to verify the FPM configuration. (Note that PHDFs are not displayed in show output because they are in XML format.)
Router(config)# load protocol disk2:ip.phdf Router(config)# load protocol disk2:udp.phdf Router(config)# class-map type stack match-all ip-udp Router(config-cmap)# description "match UDP over IP packets" Router(config-cmap)# match field ip protocol eq 0x11 next udp Router(config)# class-map type access-control match-all slammer Router(config-cmap)# description "match on slammer packets" Router(config-cmap)# match field udp dest-port eq 0x59A Router(config-cmap)# match field ip length gt 0x194 Router(config-cmap)# match start l3-start offset 224 size 4 eq 0x4011010 Router(config)# policy-map type access-control fpm-udp-policy Router(config-pmap)# description "policy for UDP based attacks" Router(config-pmap)# class slammer Router(config-pmap-c)# drop Router(config)# policy-map type access-control fpm-policy Router(config-pmap)# description "drop worms and malicious attacks" Router(config-pmap)# class ip-udp Router(config-pmap-c)# service-policy fpm-udp-policy Router(config)# interface gigabitEthernet 0/1 Router(config-if)# service-policy type access-control input fpm-policy Router# show policy-map type access-control interface gigabit 0/1 GigabitEthernet0/1 Service-policy access-control input: fpm-policy Class-map: ip-udp (match-all) 0 packets, 0 bytes 3 minute offered rate 0 bps Match: field IP protocol eq 0x11 next UDP Service-policy access-control : fpm-udp-policy Class-map: slammer (match-all) 0 packets, 0 bytes 3 minute offered rate 0 bps, drop rate 0 bps Match: field UDP dest-port eq 0x59A Match: field IP length eq 0x194 Match: start l3-start offset 224 size 4 eq 0x4011010 drop Class-map: class-default (match-any) 0 packets, 0 bytes 3 minute offered rate 0 bps, drop rate 0 bps Match: any Class-map: class-default (match-any) 0 packets, 0 bytes 3 minute offered rate 0 bps, drop rate 0 bps Match: any Router# show protocol phdf ip Protocol ID: 1 Protocol name: IP Description: Definition-for-the-IP-protocol Original file name: disk2:ip.phdf Header length: 20 Constraint(s): Total number of fields: 12 Field id: 0, version, IP-version Fixed offset. offset 0 Constant length. Length: 4 Field id: 1, ihl, IP-Header-Length Fixed offset. offset 4 Constant length. Length: 4 Field id: 2, tos, IP-Type-of-Service Fixed offset. offset 8 Constant length. Length: 8 Field id: 3, length, IP-Total-Length Fixed offset. offset 16 Constant length. Length: 16 Field id: 4, identification, IP-Identification Fixed offset. offset 32 Constant length. Length: 16 Field id: 5, flags, IP-Fragmentation-Flags Fixed offset. offset 48 Constant length. Length: 3 Field id: 6, fragment-offset, IP-Fragmentation-Offset Fixed offset. offset 51 Constant length. Length: l3 Field id: 7, ttl, Definition-for-the-IP-TTL Fixed offset. offset 64 Constant length. Length: 8 Field id: 8, protocol, IP-Protocol Fixed offset. offset 72 Constant length. Length: 8 Field id: 9, checksum, IP-Header-Checksum Fixed offset. offset 80 Constant length. Length: 16 Field id: 10, source-addr, IP-Source-Address Fixed offset. offset 96 Constant length. Length: 32 Field id: 11, dest-addr, IP-Destination-Address Fixed offset. offset 128 Constant length. Length: 32 Router# show protocol phdf udp Protocol ID: 3 Protocol name: UDP Description: UDP-Protocol Original file name: disk2:udp.phdf Header length: 8 Constraint(s): Total number of fields: 4 Field id: 0, source-port, UDP-Source-Port Fixed offset. offset 0 Constant length. Length: 16 Field id: 1, dest-port, UDP-Destination-Port Fixed offset. offset 16 Constant length. Length: 16 Field id: 2, length, UDP-Length Fixed offset. offset 32 Constant length. Length: 16 Field id: 3, checksum, UDP-Checksum Fixed offset. offset 48 Constant length. Length: 16
Example: Configuring FPM for Blaster Packets
The following example shows how to configure FPM for blaster packets. The class map contains the following match criteria: TCP port 135, 4444 or UDP port 69; and pattern 0x0030 at 3 bytes from the start of the IP header.
Router(config)# load protocol disk2:ip.phdf Router(config)# load protocol disk2:tcp.phdf Router(config)# load protocol disk2:udp.phdf Router(config)# class-map type stack match-all ip-tcp Router(config-cmap)# match field ip protocol eq 0x6 next tcp Router(config)# class-map type stack match-all ip-udp Router(config-cmap)# match field ip protocol eq 0x11 next udp Router(config)# class-map type access-control match-all blaster1 Router(config-cmap)# match field tcp dest-port eq 135 Router(config-cmap)# match start l3-start offset 3 size 2 eq 0x0030 Router(config)# class-map type access-control match-all blaster2 Router(config-cmap)# match field tcp dest-port eq 4444 Router(config-cmap)# match start l3-start offset 3 size 2 eq 0x0030 Router(config)# class-map type access-control match-all blaster3 Router(config-cmap)# match field udp dest-port eq 69 Router(config-cmap)# match start l3-start offset 3 size 2 eq 0x0030 Router(config)# policy-map type access-control fpm-tcp-policy Router(config-pmap)# class blaster1 Router(config-pmap-c)# drop Router(config-pmap-c)# class blaster2 Router(config-pmap-c)# drop Router(config)# policy-map type access-control fpm-udp-policy Router(config-pmap)# class blaster3 Router(config-pmap-c)# drop Router(config)# policy-map type access-control fpm-policy Router(config-pmap)# class ip-tcp Router(config-pmap-c)# service-policy fpm-tcp-policy Router(config-pmap)# class ip-udp Router(config-pmap-c)# service-policy fpm-udp-policy Router(config)# interface gigabitEthernet 0/1 Router(config-if)# service-policy type access-control input fpm-policy
Example: Configuring FPM for MyDoom Packets
The following example shows how to configure FPM for MyDoom packets. The match criteria is as follows:
- 90 > IP length > 44
- pattern 0x47455420 at 40 bytes from start of IP header
or
- IP length > 44
- pattern 0x6d3a3830 at 48 bytes from start of IP header
- pattern 0x47455420 at 40 bytes from start of IP header
Router(config)# load protocol disk2:ip.phdf Router(config)# load protocol disk2:tcp.phdf Router(config)# class-map type stack match-all ip-tcp Router(config-cmap)# match field ip protocol eq 0x6 next tcp Router(config)# class-map type access-control match-all mydoom1 Router(config-cmap)# match field ip length gt 44 Router(config-cmap)# match field ip length lt 90 Router(config-cmap)# match start l3-start offset 40 size 4 eq 0x47455420 Router(config)# class-map type access-control match-all mydoom2 Router(config-cmap)# match field ip length gt 44 Router(config-cmap)# match start l3-start offset 40 size 4 eq 0x47455420 Router(config-cmap)# match start l3-start offset 48 size 4 eq 0x6d3a3830 Router(config)# policy-map type access-control fpm-tcp-policy Router(config-pmap)# class mydoom1 Router(config-pmap-c)# drop Router(config-pmap-c)# class mydoom2 Router(config-pmap-c)# drop Router(config)# policy-map type access-control fpm-policy Router(config-pmap)# class ip-tcp Router(config-pmap-c)# service-policy fpm-tcp-policy Router(config)# interface gigabitEthernet 0/1 Router(config-if)# service-policy type access-control input fpm-policy
Example: Configuring and Verifying FPM on ASR Platform
The following example shows how to configure FPM on the ASR platform.
load protocol bootflash:ip.phdf load protocol bootflash:tcp.phdf class-map type stack match-all ip-tcp match field IP protocol eq 6 next TCP class-map type access-control match-all test-class match field TCP dest-port gt 10 match start l3-start offset 40 size 32 regex "ABCD" policy-map type access-control child class test-class drop policy-map type access-control parent class ip-tcp service-policy child interface GigabitEthernet0/3/0 ip address 10.1.1.1 255.0.0.0 service-policy type access-control input parent
In the following sample output, all TCP packets are seen under the class map named ip_tcp and all packets matching the specific pattern are seen under the class map named test_class. TCP packets without the specific pattern are seen under the child policy named class-default, while all non-TCP packets are seen under the parent policy named class-default. (The counter is 0 in this example.)
Router# show policy-map type access-control interface gig0/3/0
GigabitEthernet0/3/0
Service-policy access-control input: parent
Class-map: ip_tcp (match-all)
2024995578 packets, 170099628552 bytes
5 minute offered rate 775915000 bps
Match: field IP version eq 4
Match: field IP ihl eq 5
Match: field IP protocol eq 6 next TCP
Service-policy access-control : child
Class-map: test_class (match-all)
1598134279 packets, 134243279436 bytes
5 minute offered rate 771012000 bps, drop rate 771012000 bps
Match: field TCP dest-port gt 10
Match: start l3-start offset 40 size 32 regex "ABCD"
drop
Class-map: class-default (match-any)
426861294 packets, 35856348696 bytes
5 minute offered rate 4846000 bps, drop rate 0 bps
Match: any
Class-map: class-default (match-any)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: any
Router#
Example: Configuring Session-based FPM
The following example shows how to configure a class map and policy map to specify the protocol stack class, the match criteria and action to take, and a combination of classes using session-based (flow-based) and nonsession-based actions. The drop all command is associated with the action to be taken on the policy.
Router(config)# class-map type access-control match-all my-HTTP Router(config-cm)# match field tcp destport eq 8080 Router(config-cm)# match start tcp payload-start offset 20 size 10 regex "GET" Router(config)# class-map type access-control match-all my-FTP Router(config-cmap)# match field tcp destport eq 21 Router(config)# class-map type access-control match all class1 Router(config-cmap)# match class my-HTTP session Router(config-cmap)# match start tcp payload-start offset 40 size 20 regex "abc.*def" Router(config)# policy-map type access-control my_http_policy Router(config-pmap)# class class1 Router(config-pmap-c)# drop all Router(config)# interface gigabitEthernet 0/1 Router(config-if)# service-policy type access-control input my_http_policy
Example: Configuring Session-based FPM with a Filter for Increased Performance and Accuracy
The following example shows how to configure a class map and policy map to specify the protocol stack class, the match criteria and action to take, and a combination of classes using session-based (flow-based) and nonsession-based actions. However, this example uses the match class packet-range command, which acts as a filter mechanism to increases the performance and matching accuracy of the regex-based FPM class map.
Router(config)# load disk2:ip.phdf Router(config)# load protocol disk2:tcp.phdf Router(config)# class-map type stack match-all ip_tcp Router(config-cmap)# description "match TCP over IP packets" Router(config-cmap)# match field ip protocol eq 6 next tcp Router(config)# class-map type access-control match-all WM Router(config-cmap) # match start tcp payload-start offset 20 size 20 regex ".*(WEBCO|WMSG|WPNS).......[LWT].*\xc0\x80" Router(config)# class-map type access-control match-all wtube Router(config-cmap) # match start tcp payload-start offset 20 size 20 regex ".*GET\x20.*HTTP\x2f(0\.9|1\.0|1\.1)\x0d\x0aHost:\x20webtube.com\x0d\x0a" Router(config)# class-map type access-control match-all doom Router(config-cmap) # match start tcp payload-start offset 20 size 20 string virus Router(config)# class-map type access-control match-all class_webco Router(config-cmap)# match class WM session Router(config-cmap)# match field ip length eq 0x194 Router(config-cmap)# match start network-start offset 224 size 4 eq 0x4011010 Router(config)# class-map type access-control match-all class_webtube Router(config-cmap)# match class wtube packet-range 1 5 session Router(config-cmap)# match class doom session Router(config-cmap)# match field ip length eq 0x194 Router(config-cmap)# match start network-start offset 224 size 4 eq 0x4011010 Router(config)# policy-map type access-control my_policy Router(config-pmap)# class class_webco Router(config-pmap-c)# log Router(config)# policy-map type access-control my_policy Router(config-pmap)# class class_webtube Router(config-pmap-c)# drop all Router(config)# policy-map type access-control P1 Router(config-pmap)# class ip_tcp Router(config-pmap-c)# service-policy my_policy Router(config)# interface gigabitEthernet 0/1 Router(config-if)# service-policy type access-control input P1
Example: Verifying FPM Package Support
The following example shows how to verify FPM Package support.
Router# show fpm package-info fpm package-info host 10.0.0.1 remote-path fpm-group/ local-path archive/ user cisco password protocol time-range weekly Router# show fpm package-group group name: fpm-weekly-update auto-load fpm package: fpm-package-45 fpm package: fpm-group-secure package action: log
Additional References
Related Documents
| Related Topic |
Document Title |
|---|---|
| Cisco IOS commands |
|
| Security commands |
Cisco IOS Security Command Reference |
| Configuring FPM using traffic classification definition files. |
"Flexible Packet Matching XML Configuration" module in the Cisco IOS Security Configuration Guide: Securing the Data Plane |
| Complete suite of quality of service (QoS) commands |
Cisco IOS Quality of Service Solutions Command Reference |
Standards
| Standards |
Title |
|---|---|
| None |
-- |
MIBs
| MIBs |
MIBs Link |
|---|---|
| None |
To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL: |
RFCs
| RFCs |
Title |
|---|---|
| None |
-- |
Technical Assistance
| Description |
Link |
|---|---|
| The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
Feature Information for Flexible Packet Matching
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
| Table 1 | Feature Information for Flexible Packet Matching |
| Feature Name |
Releases |
Feature Information |
|---|---|---|
| Flexible Packet Matching |
12.4(4)T |
FPM is a packet classification feature that allows users to define one or more classes of network traffic by pairing a set of standard matching operators with user-defined protocol header fields. The following commands were introduced or modified: class , class-map, copy interface, debug fpm event, description, load protocol, match field, match start, policy-map, service-policy, show class-map, show policy-map interface, redirect interface, show protocol phdf. |
| FPM Full Packet Filtering |
12.4(15)T |
In Cisco IOS Release 12.4(15)T, FPM supports searching for patterns up to 56 bytes long anywhere within the entire packet. Prior to 12.4(15)T, FPM only supported searching for patterns up to 32 bytes long within the first 256 bytes of the packet. |
| FPM--Packaging, eTCDF, and Full Packet Search Enhancements |
15.0(1)M |
FPM--Packaging, eTCDF and Full Packet Search Enhancements provide preconfigured FPM filters written in XML format which can be directly loaded onto a router. The following commands were introduced or modified: algorithm, cipherkey, ciphervalue, filter-hash, filter-id, filter-version, fpm package-group, fpm package-info , show fpm package-group, match encrypted, show fpm pakage-info. |
| Session-based Flexible Packet Matching |
15.1(3)T |
With the introduction of Cisco IOS Release 15.1(3)T, FPM can now match every packet against the filters specified in the class map and passes the match result to consecutive packets of the same network session. If a filter matches with malicious content in the packet's protocol header or payload, then the required action is taken to resolve the problem. The following commands were introduced or modified: match class session, drop, log. |
| Flexible Packet Matching FPM Full Packet Filtering FPM--Packaging, eTCDF, and Full Packet Search Enhancements Session-based Flexible Packet Matching |
15.2(4)M |
Effective with Cisco IOS Release 15.2(4)M, all listed FPM features are no longer available in Cisco IOS software. |
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.
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