On the ASA 5510 and higher adaptive security appliances, the interface to which you connect with ASDM is Management 0/0. For the ASA 5505 adaptive security appliance, the switch port to which you connect with ASDM is any port, except for Ethernet 0/0. For the PIX 515/515E security appliance, the interface to which you connect with ASDM is. Cisco ASA5510-SEC-BUN-K9. ASA5510-SEC-BUN-K9 - ASA 5510 Security Plus Appl with SW, HA, 2GE+3FE, 3DES/AES. ASA 5510 Security Plus Appl with SW, HA, 2GE+3FE, 3DES/AES. Network Hardware Depot.
Introduction
This document describes how to configure the Cisco Adaptive Security Appliance (ASA) Next-Generation Firewall in order to capture the desired packets with either the Cisco Adaptive Security Device Manager (ASDM) or the CLI.
Prerequisites
Requirements
This document assumes that the ASA is fully operational and is configured in order to allow the Cisco ASDM or the CLI to make configuration changes.
Components Used
This document is not restricted to specific hardware or software versions.
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
Related Products
This configuration can also be used with these Cisco products:
Cisco ASA Versions 9.1(5) and later
Cisco ASDM Version 7.2.1
Background Information
The packet capture process is useful when you troubleshoot connectivity problems or monitor suspicious activity. In addition, you can create multiple captures in order to analyze different types of traffic on multiple interfaces.
Configure
This section provides information that you can use in order to configure the packet capture features that are described in this document.
Note: Use the Command Lookup Tool (registered customers only) in order to obtain more information on the commands used in this section.
Network Diagram
This document uses this network setup:
Configurations
Note: The IP addressing schemes that are used in this configuration are not legally routable on the Internet. They are RFC 1918 addresses that are used in a lab environment.
Configure Packet Capture with the ASDM
Note: This example configuration is used in order to capture the packets that are transmitted during a ping from User1 (inside network) to Router1 (outside network).
Complete these steps in order to configure the packet capture feature on the ASA with the ASDM:
- Navigate to Wizards > Packet Capture Wizard in order to start the packet capture configuration, as shown:
- The Capture Wizard opens. Click Next.
- In the new window, provide the parameters that are used in order to capture the INGRESS traffic. Select inside for the Ingress Interface and provide the source and the destination IP addresses of the packets to be captured, along with their subnet mask, in the respective space provided. Also, choose the packet type to be captured by the ASA (IP is the packet type chosen here), as shown:
Click Next. - Select outside for the Egress Interface and provide the source and the destination IP addresses, along with their subnet mask, in the respective spaces provided. If Network Address Translation (NAT) is performed on the Firewall, take this into consideration as well.
Click Next. - Enter the appropriate Packet Size and the Buffer Size in the respective space provided, as this data is required in order for the capture to take place. Also, remember to check the Use circular buffer check box if you want to use the circular buffer option. Circular buffers never fill up. As the buffer reaches its maximum size, older data is discarded and the capture continues. In this example, circular buffer is not used, so the check box is not checked.
Click Next. - This window shows the Access-lists that must be configured on the ASA so that the desired packets are captured, and it shows the type of packets to be captured (IP packets are captured in this example). Click Next.
- Click Start in order to start the packet capture, as shown here:
- As the packet capture is started, attempt to ping the outside network from the inside network so that the packets that flow between the source and the destination IP addresses are captured by the ASA capture buffer.
- Click Get Capture Buffer in order to view the packets that are captured by the ASA capture buffer.
- The captured packets are shown in this window for both the ingress and egress traffic. Click Save captures in order to save the capture information.
- From the Save Captures window, choose the required format in which the capture buffer is to be saved. This is either ASCII or PCAP. Click the radio button next to the format names. Then, click Save ingress capture or Save egress capture as required. The PCAP files can be opened with capture analyzers, such as Wireshark, and it is the preferred method.
- From the Save capture file window, provide the file name and the location to where the capture file is to be saved. Click Save.
- Click Finish.
This completes the packet capture procedure.
Configure Packet Capture with the CLI
Complete these steps in order to configure the packet capture feature on the ASA with the CLI:
- Configure the inside and outside interfaces as illustrated in the network diagram, with the correct IP address and security levels.
- Start the packet capture process with the capture command in privileged EXEC mode. In this configuration example, the capture named capin is defined. Bind it to the inside interface, and specify with the match keyword that only the packets that match the traffic of interest are captured:
- Similarly, the capture named capout is defined. Bind it to the outside interface, and specify with the match keyword that only the packets that match the traffic of interest are captured:
The ASA now begins to capture the traffic flow between the interfaces. In order to stop the capture at anytime, enter the no capture command followed by the capture name.
Here is an example:
Available Capture Types on the ASA
This section describes the different types of captures that are available on the ASA.
- asa_dataplane - Captures packets on the ASA backplane that pass between the ASA and a module that uses the backplane, such as the ASA CX or IPS module.
- asp-drop drop-code - Captures packets that are dropped by the accelerated security path. The drop-code specifies the type of traffic that is dropped by the accelerated security path.
- ethernet-type type - Selects an Ethernet type to capture. Supported Ethernet types include 8021Q, ARP, IP, IP6, IPX, LACP, PPPOED, PPPOES, RARP, and VLAN.
This example show how to capture ARP traffic: - real-time - Displays the captured packets continuously in real-time. In order to terminate a real-time packet capture, press Ctrl-C. In order to permanently remove the capture, use the no form of this command. This option is not supported when you use the cluster exec capture command.
- Trace - Traces the captured packets in a manner similar to the ASA packet tracer feature.
- ikev1/ikev2 - Captures only Internet Key Exchange Version 1 (IKEv1) or IKEv2 protocol information.
- isakmp - Captures Internet Security Association and Key Management Protocol (ISAKMP) traffic for VPN connections. The ISAKMP subsystem does not have access to the upper-layer protocols. The capture is a pseudo capture, with the physical, IP, and UDP layers combined together in order to satisfy a PCAP parser. The peer addresses are obtained from the SA exchange and are stored in the IP layer.
- lacp - Captures Link Aggregation Control Protocol (LACP) traffic. If configured, the interface name is the physical interface name. This might be useful when you work with Etherchannels in order to identify the present behavior of LACP.
- tls-proxy - Captures decrypted inbound and outbound data from the Transport Layer Security (TLS) proxy on one or more interfaces.
- webvpn - Captures WebVPN data for a specific WebVPN connection.
Caution: When you enable WebVPN capture, it affects the performance of the security appliance. Ensure that you disable the capture after you generate the capture files that are needed in order to troubleshoot.
Defaults
These are the ASA system default values:
- The default type is raw-data.
- The default buffer size is 512 KB.
- The default Ethernet type is IP packets.
- The default packet-length is 1,518 bytes.
View the Captured Packets
On the ASA
In order to view the captured packets, enter the show capture command followed by the capture name. This section provides the show command outputs of the capture buffer contents. The show capture capin command shows the contents of the capture buffer named capin:
The show capture capout command shows the contents of the capture buffer named capout:
Release Notes For Cisco ASA 5500 Version 7.2(5) - Cisco
Download from the ASA for Offline Analysis
There are a couple of ways to download the packet captures for analysis offline:
- Navigate to https://<ip_of_asa>/admin/capture/<capture_name>/pcap on any browser.
Tip: If you leave out the pcap keyword, then only the equivalent of the show capture <cap_name> command output is provided.
- Enter the copy capture command and your preferred file transfer protocol in order to download the capture:
Tip: When you troubleshoot an issue with the use of packet captures, Cisco recommends that you download the captures for offline analysis.
Clear a Capture
In order to clear the capture buffer, enter the clear capture <capture-name> command:
Enter the clear capture /all command in order to clear the buffer for all captures:
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Stop a Capture
The only way to stop a capture on the ASA is to disable it completely with this command:
Cisco bug ID CSCuv74549 has been filed to add the ability to stop a capture without completely disabling it and to control when a capture starts to capture traffic.
Verify
There is currently no verification procedure available for this configuration.
ASA Packet Captures With CLI And ASDM Configuration ... - Cisco
Troubleshoot
Migrating From ASA5505 7.2 To ASA5510 8.3 - Cisco Community
There is currently no specific troubleshooting information available for this configuration.