CISCODUMP(1) CISCODUMP(1)
NAME
ciscodump - Provide interfaces to capture from a remote Cisco device
through SSH.
SYNOPSIS
ciscodump [ --help ] [ --version ] [ --extcap-interfaces ]
[ --extcap-dlts ] [ --extcap-interface=<interface> ]
[ --extcap-config ] [ --extcap-capture-filter=<capture filter> ]
[ --capture ] [ --fifo=<path to file or pipe> ]
[ --remote-host=<IP address> ] [ --remote-port=<TCP port> ]
[ --remote-username=<username> ] [ --remote-password=<password> ]
[ --remote-filter=<filter> ] [ --sshkey=<public key path> ]
[ --remote-interface=<interface> ] [ --remote-count=<count> ]
ciscodump --extcap-interfaces
ciscodump --extcap-interface=ciscodump --extcap-dlts
ciscodump --extcap-interface=ciscodump --extcap-config
ciscodump --extcap-interface=ciscodump --fifo=<path to file or pipe>
--capture --remote-host=remotedevice --remote-port=22
--remote-username=user --remote-interface=<the device interface>
--remote-count=<count>
DESCRIPTION
Ciscodump is an extcap tool that relies on Cisco EPC to allow a user to
run a remote capture on a Cisco device in a SSH connection. It supports
IOS, IOS-XE based device and ASA devices.
The tool configures capture on the device, reads data and removes
configuration from the device. Provided credentials must allow the tool
to configure the device.
When capture is started, packets are provided as they are received from
the device. Capture stops when:
• requested count of packets is reached (--remote-count is mandatory)
• when capture finishes on the device (e.g. capture buffer is full)
• the capture is stopped by the user
Capture performance depends on a device type. The tool tries to read
packets as soon as they received, but is usually slower than capturing
device captures packets. Therefore packets are read in batches.
IOS/IOS-XE provides only access to all captured packets from the top.
Therefore reading of second batch means to read all packets from first
batch, but ignore them and then read new packets in second batch.
ASA provides access to specific packet so tool reads every packet just
once.
SUPPORTED CISCO SOFTWARE
The application supports IOS version is 12.4 and higher. The IOS
version supporting capture feature is 12.4(20)T and higher. More
details can be found here:
https://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/ios-embedded-packet-capture/datasheet_c78-502727.html
The application supports IOS-XE version 16.1 and higher. Search for
"Embedded Packet Capture Configuration Guide, Cisco IOS XE" to get more
details.
The application supports ASA version 8.4 and higher. More details can
be found here:
https://community.cisco.com/t5/security-documents/asa-using-packet-capture-to-troubleshoot-asa-firewall/ta-p/3129889
OPTIONS
--help
Print program arguments.
--version
Print program version.
--extcap-interfaces
List available interfaces.
--extcap-interface=<interface>
Use specified interfaces.
--extcap-dlts
List DLTs of specified interface.
--extcap-config
List configuration options of specified interface.
--capture
Start capturing from specified interface and save it in place
specified by --fifo.
--fifo=<path to file or pipe>
Save captured packet to file or send it through pipe.
--remote-host=<remote host>
The address of the remote host for capture.
--remote-port=<remote port>
The SSH port of the remote host.
--remote-username=<username>
The username for ssh authentication.
--remote-password=<password>
The password to use (if not ssh-agent and pubkey are used).
WARNING: the passwords are stored in plaintext and visible to all
users on this system. It is recommended to use keyfiles with a SSH
agent.
--remote-filter=<filter>
The remote filter on the device. This is a capture filter that
follows the Cisco standards.
For IOS/IOS-XE see
https://www.cisco.com/c/en/us/support/docs/ip/access-lists/26448-ACLsamples.html.
For ASA see
https://www.cisco.com/c/en/us/td/docs/security/asa/asa96/configuration/firewall/asa-96-firewall-config/access-acls.html.
Multiple filters can be specified using a comma between them.
BEWARE: when using a filter, the default behavior is to drop all
the packets except the ones that fall into the filter.
Examples for IOS/IOS-XE:
permit ip host MYHOST any, permit ip any host MYHOST (capture the traffic for MYHOST)
deny ip host MYHOST any, deny ip any host MYHOST, permit ip any any (capture all the traffic except MYHOST)
Examples for ASA:
permit any4 host MYHOST, permit host MYHOST any4 (capture IPv4 traffic for MYHOST)
Note
Different capture types support or do not support specific ACL
keywords. The tool is not able to check it, just tries to
configure it. If error occurs, the tool just reports it and
terminates. Debris are left in configuration in this case.
--sshkey=<SSH private key path>
The path to a private key for authentication.
--remote-interface=<remote interface>
The remote network interface to capture from. One interface or list
of interface names can be used. Iterfaces are separated by comma.
Interface names must be supported by the device.
There are interface names causing different capture types. They are
specific to used Cisco software.
IOS special names
• process-switched - capture process switched packets in both
directions
• from-us - capture process switched packets originating at the
device
IOS-XE special names
• control-plane - captures in/out packets touching control plane
ASA special names
• asp-drop - capture packets dropped by all asp categories
• TYPE---ifname - syntax to refer ASA capture types, see
https://www.cisco.com/c/en/us/td/docs/security/asa/asa-cli-reference/A-H/asa-command-ref-A-H/ca-cld-commands.html#wp2435483314
• isakmp---ifname - capture isakmp packets
• lacp---ifname - capture lacp packets (just physical
interfaces are supported)
• tls-proxy---ifname - capture tls-proxy packets
• inline-tag---ifname - capture all SGT tagget packets
• raw-data---ifname - same as ifname
• syntax to capture decrypted traffic for some of capture types:
• isakmp/decrypted---ifname - capture isakmp packets
including decrypted payload
• tls-proxy/decrypted---ifname - capture tls-proxy packets
including decrypted payload
• inline-tag/decrypted---ifname - capture inline-tag packets
including decrypted payload
• raw-data/decrypted---ifname - capture raw-data packets
including decrypted payload
Use e. g. isakmp/decrypted---outside to capture encrypted and
decrypted isakmp traffic on outside interface.
--remote-count=<count>
Count of packets to capture. Capture is stopped when count is
reached.
--extcap-capture-filter=<capture filter>
Unused (compatibility only).
EXAMPLES
To see program arguments:
ciscodump --help
To see program version:
ciscodump --version
To see interfaces:
ciscodump --extcap-interfaces
Only one interface (ciscodump) is supported.
Example output
interface {value=ciscodump}{display=SSH remote capture}
To see interface DLTs:
ciscodump --extcap-interface=ciscodump --extcap-dlts
Example output
dlt {number=147}{name=ciscodump}{display=Remote capture dependent DLT}
To see interface configuration options:
ciscodump --extcap-interface=ciscodump --extcap-config
Example output
ciscodump --extcap-interface=ciscodump --extcap-config
arg {number=0}{call=--remote-host}{display=Remote SSH server address}
{type=string}{tooltip=The remote SSH host. It can be both an IP address or a hostname}
{required=true}{group=Server}
arg {number=1}{call=--remote-port}{display=Remote SSH server port}
{type=unsigned}{default=22}{tooltip=The remote SSH host port (1-65535)}
{range=1,65535}{group=Server}
arg {number=2}{call=--remote-username}{display=Remote SSH server username}
{type=string}{default=<current user>}{tooltip=The remote SSH username. If not provided, the current user will be used}
{group=Authentication}
arg {number=3}{call=--remote-password}{display=Remote SSH server password}
{type=password}{tooltip=The SSH password, used when other methods (SSH agent or key files) are unavailable.}
{group=Authentication}
arg {number=4}{call=--sshkey}{display=Path to SSH private key}
{type=fileselect}{tooltip=The path on the local filesystem of the private ssh key}
{group=Authentication}
arg {number=5}{call=--proxycommand}{display=ProxyCommand}
{type=string}{tooltip=The command to use as proxy for the SSH connection}{group=Authentication}
arg {number=6}{call--sshkey-passphrase}{display=SSH key passphrase}
{type=password}{tooltip=Passphrase to unlock the SSH private key}{group=Authentication
arg {number=7}{call=--remote-interface}{display=Remote interface}
{type=string}{tooltip=The remote network interface used for capture}
{required=true}{group=Capture}
arg {number=8}{call=--remote-filter}{display=Remote capture filter}
{type=string}{tooltip=The remote capture filter}{default=<filter to exclude current host>}
{group=Capture}
arg {number=9}{call=--remote-count}{display=Packets to capture}
{type=unsigned}{tooltip=The number of remote packets to capture.}
{required=true}{group=Capture}
arg {number=10}{call=--debug}{display=Run in debug mode}
{type=boolflag}{default=false}{tooltip=Print debug messages}
{required=false}{group=Debug}
arg {number=11}{call=--debug-file}{display=Use a file for debug}
{type=string}{tooltip=Set a file where the debug messages are written}
{required=false}{group=Debug}
To capture on IOS/IOS-XE:
ciscodump --extcap-interface ciscodump --fifo=/tmp/cisco.pcap --capture --remote-host 192.168.1.10
--remote-username user --remote-interface gigabit0/0,gigiabit0/1
--remote-filter "permit ip host 192.168.1.1 any, permit ip any host 192.168.1.1"
--remote-count=10
To capture on IOS/IOS-XE:
ciscodump --extcap-interface ciscodump --fifo=/tmp/cisco.pcap --capture --remote-host 192.168.1.10
--remote-username user --remote-interface outside,dmz
--remote-filter "permit host 192.168.1.1 any4, permit any4 host 192.168.1.1"
--remote-count=10
ciscodump --extcap-interface ciscodump --fifo=/tmp/cisco.pcap --capture --remote-host 192.168.1.10
--remote-username user --remote-interface raw-data/decrypted---outside
--remote-filter "permit host 192.168.1.1 any4, permit any4 host 192.168.1.1"
KNOWN ISSUES
When capture stopped by the user before it finishes on Windows
platform, configuration is not cleared on the device. Next run will
probably fails because parts of configuration already exists on the
device.
Reading performance on IOS/IOS-XE is poor because re-reading of capture
buffer over and over.
The configuration of the capture on the device is a multi-step process.
If the SSH connection is interrupted during it, the configuration can
be in an inconsistent state. That can happen also if the capture is
stopped and ciscodump can’t clean the configuration up. In this case it
is necessary to log into the device and manually clean the
configuration, removing configuration elements:
• IOS
• capture points WSC_P_<number> (depends on count of capture
interfaces)
• the capture buffer WSC_B
• the capture capture acl WSC_ACL (if filter was used)
• IOS-XE
• the capture WSC
• the capture capture acl WSC_ACL (if filter was used)
• ASA
• the capture WSC
• the capture capture acl WSC_ACL (if filter was used)
On IOS platforms, only IPv4 commands issued and only IPv4 packets are
captured.
SEE ALSO
wireshark(1), tshark(1), dumpcap(1), extcap(4), sshdump(1)
NOTES
ciscodump is part of the Wireshark distribution. The latest version of
Wireshark can be found at https://www.wireshark.org.
HTML versions of the Wireshark project man pages are available at
https://www.wireshark.org/docs/man-pages.
AUTHORS
Original Author
Dario Lombardo <lomato[AT]gmail.com>
2023-11-17 CISCODUMP(1)
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