Home > Articles > Cisco Certification > CCNP Security / CCSP > CCNP Security Firewall Cert Guide: Recording ASA Activity

CCNP Security Firewall Cert Guide: Recording ASA Activity

Chapter Description

To help you prepare for the CCNP Security Firewall 642-617 exam, this chapter covers System Time, Managing Event and Session Logging, Configuring Event and Session Logging, Verifying Event and Session Logging, and Troubleshooting Event and Session Logging.

Managing Event and Session Logging

The Cisco Adaptive Security Appliance supports a full audit trail of system log messages that describe its activities and security events. The two major classifications of events are system events, such as resource depletion, and network events, such as denied sessions or packets. These messages are used to create log files, which can be filtered and sent to a number of differing destinations for storage, display, or analysis.

Figure 6-4 provides a graphical illustration of the Cisco ASA logging subsystem, showing the two major event classifications as sources, and the eight possible destinations.

Figure 6-4

Figure 6-4 The Cisco ASA Logging Subsystem

The security appliance supports sending log messages to the following destinations:

  • Console: The security appliance console, a low-bandwidth serial connection to which messages can be sent for display on a console CLI session. This mode is useful for limited debugging, or in production environments with limited traffic or a lack of centralized management tools.
  • ASDM: The ASDM graphical user interface, which provides a powerful real-time event viewer useful for troubleshooting issues or monitoring network activity.
  • Monitor: Telnet or SSH administrative sessions. This mode is useful to receive real-time debugging information when troubleshooting.
  • Buffered: The internal in-memory buffer on the security appliance. Although useful for storage and analysis of recent activity, the internal buffer is limited in size, and it is not persistent, by default, across appliance reboots. The buffer can optionally be archived to an external FTP server or to the security appliance's internal flash memory.
  • Host: Remote syslog servers, using the standard syslog protocol. Use the logging host command in conjunction with the logging trap command to define both a destination server and a logging level.
  • SNMP: Remote network management servers, using the standard Simple Network Management Protocol (SNMP) Trap to send event messages. This mode is configured with the snmp-server enable traps syslog command, rather than directly with a logging destination command.
  • Mail: Remote email systems, using the standard Simple Mail Transfer Protocol (SMTP) to send event messages to a defined SMTP server, or set of SMTP servers.
  • Flow-export-syslogs: Remote NetFlow collectors, using the standard NetFlow v9 protocol to send event messages to the defined collector.

NetFlow Support

Cisco NetFlow efficiently provides a key set of services for IP applications, including network traffic accounting, usage-based network billing, network planning, security, denial-of-service monitoring capabilities, and network monitoring. NetFlow provides valuable information about network users and applications, peak usage times, and traffic routing.

The basic output of NetFlow is known as a flow record. Several different formats for flow records have existed as NetFlow has evolved and matured. The current version of NetFlow formatting is known as NetFlow version 9. The Cisco ASA supports providing NetFlow Secure Event Logging (NSEL), beginning with version 8.2(1). NSEL allows specific, high-volume, traffic-related events to be exported from the security appliance in a more efficient and scalable manner than that provided by standard syslog logging. You may use any NetFlow v9–capable collector to receive ASA NetFlow data.

The ASA implementation of NSEL is a stateful, IP flow tracking method that exports only those records that indicate significant events in a flow. In stateful flow tracking, tracked flows go through a series of state changes. NSEL events are used to export data about flow status, and are triggered by the events that cause state changes. Examples of events that are tracked include flow-create, flow-teardown, and flow-denied (excluding flows that are denied by EtherType ACLs, which are discussed in Chapter 12, "Using Transparent Firewall Mode"). Each NSEL record has an event ID and an extended event ID field, which describe the flow event.

The Cisco ASA supports multiple NetFlow export destinations and can therefore store its NetFlow information on multiple NetFlow collectors.

For a detailed discussion on Cisco ASA NetFlow event generation, consult the "Cisco ASA 5500 Series Implementation Note for NetFlow Collectors, 8.2," at www.cisco.com/en/US/docs/security/asa/asa82/netflow/netflow.html.


Logging Message Format

Most Cisco ASA messages generated by the logging subsystem are simple text messages that conform to a particular message format, as demonstrated here:

Jan 5 2011 09:27:16 FIREWALL : %ASA-6-725002: Device completed SSL handshake with
  client management:

This message consists of the following:

  • An optional timestamp (disabled by default)
  • An optional device-id (disabled by default), which can include the interface name, IP address, hostname, context name, or a custom string up to 16 characters, if configured
  • A message identifier (%ASA-6-725002 in the example), which identifies the device type (ASA), the message severity level (6, Informational), and the event message number (725002)
  • The message text (Device completed SSL handshake...)

Additional data may be added to the message, depending on its destination. For example, a time stamp and hostname may be added for the syslog destination.

Message Severity

Each log message is assigned a severity level that indicates its relative importance. Lower numbers are of higher severity than higher numbers. Possible number and string values for message severity are shown in Table 6-2.


Table 6-2. Message Severity Levels

Numeric Level

Equivalent String




Extremely critical "system unusable" messages



Messages that require immediate administrator action



A critical condition



An error message (also the level of many access list deny messages)



A warning message (also the level of many other access list deny messages)



A normal but significant condition (such as an interface coming online)



An informational message (such as a session being created or torn down)



A debug message or very detailed accounting message

5. Configuring Event and Session Logging | Next Section Previous Section

Cisco Press Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from Cisco Press and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Cisco Press products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites; develop new products and services; conduct educational research; and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@ciscopress.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by Cisco Press. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.ciscopress.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020