2023-11-28T18:55:20+03:00[Europe/Moscow] en true <p>Any traffic coming to or from the <span class="tt-bg-red">___</span> of the Arista is visible when running the tcpdump utility on the Arista.</p>, <p><strong>tcpdump</strong>&nbsp;allows users to instantly analyze important traffic such as <span class="tt-bg-red">___</span>, as well as any other traffic that is destined for the switch itself.</p>, <p>The Linux&nbsp;<span class="tt-bg-red">___</span>&nbsp;command can be used to see the available interfaces in the Linux kernel.</p>, <p>ifconfig: The list of interfaces will reflect each of the physical interfaces on the Arista switch as well as any <span class="tt-bg-red">___</span> interfaces.</p>, <p>Any VLAN which has been assigned an <span class="tt-bg-red">___</span> will show up as a VLAN interface.</p>, <p>Filter by VLAN interface</p>, <p>The ‘-v’ and ‘-vv’ flags can be used to provide <span class="tt-bg-red">___</span> output.</p>, <p>Filter traffic on a specific destination port number</p><p></p>, <p>List all network interfaces available for capture</p>, <p>By default, tcpdump attempts to resolve IP addresses and port numbers into <span class="tt-bg-red">___</span></p>, <p>Disable hostname resolution using the <span class="tt-bg-red">__</span> flag.</p>, <p>Disable hostname AND port name resolution using the <span class="tt-bg-red">__</span> flag.</p>, <p>Stop capturing after 10 packets</p>, <p>Filter by IP address (source or destination) using 10.95.65.1</p>, <p>Filter traffic by interface po50</p>, <p>Filter traffic by source IP address, using 10.95.65.1</p>, <p>Filter traffic by destination IP address, using 10.95.65.1</p>, <p>Filter traffic by protocol (ICMP)</p>, <p>Filter traffic to or from host 10.95.65.1 of type ICMP. Disable name/port resolution and limit capture to 5 packets.</p>, <p>Filter SSH traffic destined to host 10.95.65.1</p>, <p>How do I see LLDP packets coming from an interface?</p><p></p>, <p>My server is port-channeled to my Arista switch, and it is not coming up.&nbsp; How do I capture LACP packets coming to and from the server to form the port-channel?</p>, Filter LLDP traffic on interface Ethernet4/22/1, <p>LLDP well-known multicast MAC address</p>, <p>LACP well-known multicast MAC address</p>, Filter LACP traffic on interface Ethernet4/22/1, <p>Filter SSL traffic to/from IP 10.95.65.1 on Management0. Write the capture to test.pcap on flash.</p>, <p>Read the first packet from test.pcap in Flash. Disable IP and port name resolution.</p>, <p>How do I capture OSPF packets between neighbors?</p>, <p>Listen on all interfaces just to see if you're seeing any traffic.</p>, <p>Increase the amount of packet information you get back.</p>, <p>Show the packet’s contents in both hex and ASCII.</p>, <p>Same as -X, but also shows the ethernet header.</p>, <p>Only get x number of packets and then stop.</p>, <p>Print absolute sequence numbers.</p>, <p>Show minimal protocol information.</p>, <p>Filtering for a specific host with VLAN tags</p>, <p>Filtering for either arp or icmp <strong>without</strong> VLAN tags</p>, <p>Filtering for either arp or icmp <strong>with</strong> VLAN tags</p>, <p>Filtering for either arp or icmp with or without VLAN tags</p>, <p>The ‘vlan’ keyword in a tcpdump filter changes the lookup offsets for all other keywords <span class="tt-bg-red">___</span> the keyword.&nbsp; This behavior is irrespective of parentheses.</p>, <p>Filter for BPDUs <strong>Without</strong> VLAN tags i.e. RSTP/MSTP/untagged native VLAN in Rapid PVST</p>, <p>Filter for BPDUs <strong>With</strong> VLAN tags i.e. tagged VLAN BPDUs in Rapid PVST</p>, <p>Print all packets but <strong>NOT</strong> those from host 00:25:90:32:ec:2a </p>, <p>Filter for VXLAN VNI 200</p>, <p>Filter for a VXLAN inner destination of&nbsp;MAC 28:99:3a:8f:b1:41</p>, <p>Filter for a VXLAN inner source MAC of&nbsp;28:99:3a:8f:ae:a7</p>, <p>Filter for a VXLAN iinner source IP of 20.20.20.10</p>, <p>Filter for a VXLAN inner destination IP of 20.20.20.5</p>, <p>we can punt traffic to CPU to take captures. It will <span class="tt-bg-red">___</span> the CPU as policies rate limiting traffic to CPU are in place (about 1Gb/s)</p>, <p>LACP packets must be viewed on <span class="tt-bg-red">___</span>, not the port-channel!</p>, <p>Filtered Mirroring ___: Configure an ACL with entries that match traffic we are interested in (TX, RX, or both) ending with "mirror session &lt;session name&gt;"</p>, <p>Filtered Mirroring ___: Set the last ACL rule as permit ip any any (If the interface doesn’t already have an ACL)</p>, <p>Filtered Mirroring ___: Assign the ACL to the interface we would like to capture traffic on</p>, <p>Filtered Mirroring ___: Add a destination monitor session port Ethernet, Port-channel, CPU or Tunnel</p>, <p>Filtered Mirroring: Associate ACL entries with a monitor session using the key words ___</p>, <p>Print traffic from the monitor session pictured. Filter traffic to/from host 10.95.65.1. Disable host name and port name resolutions.</p>, <p>Configure the switch to automatically send sampled LANZ traffic to the CPU</p>, <p>Enable LANZ</p>, <p>Configure the switch to enable packet sampling of LANZ traffic</p>, <p>This command configures a port mirroring session to truncate mirrored packets, retaining only the first 128-192 bytes.</p>, <p>Packet truncation can be used to prevent ___ of a monitor session’s destination port. It helps control the utilization of the Mirror CoPP.&nbsp;</p>, <p>packet ___ applies to the mirroring session as a whole, and cannot be applied to individual source ports.</p>, <p>On Sand, the size of truncated packets can be set to either ___ or ___ bytes.</p>, <p>On Strata/Alta, the number of bytes to be retained when truncating packets is fixed at <strong>___</strong></p> flashcards
TCPDump

TCPDump

  • Any traffic coming to or from the ___ of the Arista is visible when running the tcpdump utility on the Arista.

    control plane

  • tcpdump allows users to instantly analyze important traffic such as ___, as well as any other traffic that is destined for the switch itself.

    spanning tree and routing protocols

  • The Linux&nbsp;___&nbsp;command can be used to see the available interfaces in the Linux kernel.

    The Linux ___ command can be used to see the available interfaces in the Linux kernel.

    ifconfig

  • ifconfig: The list of interfaces will reflect each of the physical interfaces on the Arista switch as well as any ___ interfaces.

    virtual

  • Any VLAN which has been assigned an ___ will show up as a VLAN interface.

    IP address (SVI)

  • Filter by VLAN interface

    bash tcpdump -i vlan1026

  • The ‘-v’ and ‘-vv’ flags can be used to provide ___ output.

    more detailed

  • Filter traffic on a specific destination port number

    bash tcpdump dst port 22

  • List all network interfaces available for capture

    List all network interfaces available for capture

    bash tcpdump -D

  • By default, tcpdump attempts to resolve IP addresses and port numbers into ___

    names

  • Disable hostname resolution using the __ flag.

    Disable hostname resolution using the __ flag.

    -n

  • Disable hostname AND port name resolution using the __ flag.

    Disable hostname AND port name resolution using the __ flag.

    -nn

  • Stop capturing after 10 packets

    bash tcpdump -c 10

  • Filter by IP address (source or destination) using 10.95.65.1

    bash tcpdump host 10.95.65.1

  • Filter traffic by interface po50

    bash tcpdump -i po50

  • Filter traffic by source IP address, using 10.95.65.1

    bash tcpdump src 10.95.65.1

  • Filter traffic by destination IP address, using 10.95.65.1

    bash tcpdump dst 10.95.65.1

  • Filter traffic by protocol (ICMP)

    bash tcpdump icmp

  • Filter traffic to or from host 10.95.65.1 of type ICMP. Disable name/port resolution and limit capture to 5 packets.

    bash tcpdump -nnc5 host 10.95.65.1 and icmp

  • Filter SSH traffic destined to host 10.95.65.1

    bash tcpdump dst 10.95.65.1 and port 22

  • How do I see LLDP packets coming from an interface?

    bash tcpdump -i et1 ether dst host 01:80:c2:00:00:0e

  • My server is port-channeled to my Arista switch, and it is not coming up.  How do I capture LACP packets coming to and from the server to form the port-channel?

    bash tcpdump -nevvi et1 ether host 01:80:c2:00:00:02

  • Filter LLDP traffic on interface Ethernet4/22/1
    Filter LLDP traffic on interface Ethernet4/22/1

    bash tcpdump -i et4_22_1 ether host 01:80:c2:00:00:0e ... or bash tcpdump -i et4_22_1 ether proto 0x88cc

  • LLDP well-known multicast MAC address

    01:80:c2:00:00:0e
  • LACP well-known multicast MAC address

    01:80:c2:00:00:02

  • Filter LACP traffic on interface Ethernet4/22/1
    Filter LACP traffic on interface Ethernet4/22/1

    bash tcpdump -i et4_22_1 ether host 01:80:c2:00:00:02 ... or bash tcpdump -i et4_22_1 ether proto 0x8809)

  • Filter SSL traffic to/from IP 10.95.65.1 on Management0. Write the capture to test.pcap on flash.

    bash tcpdump -nni ma0 host 10.95.65.1 and port 22 -w flash:test.pcap

  • Read the first packet from test.pcap in Flash. Disable IP and port name resolution.

    bash tcpdump -nnc1 -r flash:test.pcap

  • How do I capture OSPF packets between neighbors?

    bash tcpdump -nnevi po50 proto ospf

  • Listen on all interfaces just to see if you're seeing any traffic.

    -i any

  • Increase the amount of packet information you get back.

    -v, -vv, -vvv

  • Show the packet’s contents in both hex and ASCII.

    -X

  • Same as -X, but also shows the ethernet header.

    -XX

  • Only get x number of packets and then stop.

    -c

  • Print absolute sequence numbers.

    Print absolute sequence numbers.

    -S

  • Show minimal protocol information.

    Show minimal protocol information.

    -q

  • Filtering for a specific host with VLAN tags

    bash tcpdump -i ma0 vlan and host 10.95.65.1

  • Filtering for either arp or icmp without VLAN tags

    bash tcpdump -i ma0 arp or icmp

  • Filtering for either arp or icmp with VLAN tags

    bash tcpdump -i ma0 vlan and '(arp or icmp)'

  • Filtering for either arp or icmp with or without VLAN tags

    bash tcpdump -i ma0 '(arp or icmp) or (vlan and (arp or icmp))'

  • The ‘vlan’ keyword in a tcpdump filter changes the lookup offsets for all other keywords ___ the keyword.  This behavior is irrespective of parentheses.

    following

  • Filter for BPDUs Without VLAN tags i.e. RSTP/MSTP/untagged native VLAN in Rapid PVST

    Filter for BPDUs Without VLAN tags i.e. RSTP/MSTP/untagged native VLAN in Rapid PVST

    bash tcpdump -i ma0 stp ... or bash tcpdump -i ma0 ether proto 0x42)

  • Filter for BPDUs With VLAN tags i.e. tagged VLAN BPDUs in Rapid PVST

    bash tcpdump -i ma0 vlan and ether dst 01:00:0c:cc:cc:cd
  • Print all packets but NOT those from host 00:25:90:32:ec:2a

    bash tcpdump -i ma0 not ether src 00:25:90:32:ec:2a

  • Filter for VXLAN VNI 200

    bash tcpdump -i ma0 'port 4789 and udp[8:2] = 0x0800 and udp[11:4] = 200'

  • Filter for a VXLAN inner destination of MAC 28:99:3a:8f:b1:41

    bash tcpdump -i ma0 'port 4789 and udp[8:2] = 0x0800 and udp[16:4] = 0x28993a8f and udp[20:2] = 0xb141'

  • Filter for a VXLAN inner source MAC of 28:99:3a:8f:ae:a7

    bash tcpdump -i ma0 'port 4789 and udp[8:2] = 0x0800 and udp[22:4] = 0x28993a8f and udp[26:2] = 0xaea7'

  • Filter for a VXLAN iinner source IP of 20.20.20.10

    bash tcpdump -i ma0 'port 4789 and udp[8:2] = 0x0800 and udp[42:4] = 0x1414140a'

  • Filter for a VXLAN inner destination IP of 20.20.20.5

    bash tcpdump -i ma0 'port 4789 and udp[8:2] = 0x0800 and udp[46:4] = 0x14141405'

  • we can punt traffic to CPU to take captures. It will ___ the CPU as policies rate limiting traffic to CPU are in place (about 1Gb/s)

    not overwhelm

  • LACP packets must be viewed on ___, not the port-channel!

    physical interfaces

  • Filtered Mirroring ___: Configure an ACL with entries that match traffic we are interested in (TX, RX, or both) ending with "mirror session <session name>"

    Step 1

  • Filtered Mirroring ___: Set the last ACL rule as permit ip any any (If the interface doesn’t already have an ACL)

    Step 2

  • Filtered Mirroring ___: Assign the ACL to the interface we would like to capture traffic on

    Step 3

  • Filtered Mirroring ___: Add a destination monitor session port Ethernet, Port-channel, CPU or Tunnel

    Step 4

  • Filtered Mirroring: Associate ACL entries with a monitor session using the key words ___

    Filtered Mirroring: Associate ACL entries with a monitor session using the key words ___

    mirror session

  • Print traffic from the monitor session pictured. Filter traffic to/from host 10.95.65.1. Disable host name and port name resolutions.

    Print traffic from the monitor session pictured. Filter traffic to/from host 10.95.65.1. Disable host name and port name resolutions.

    bash tcpdump -nni mirror0 host 10.95.65.1

  • Configure the switch to automatically send sampled LANZ traffic to the CPU

    Configure the switch to automatically send sampled LANZ traffic to the CPU

    queue-monitor length mirror destination cpu

  • Enable LANZ

    Enable LANZ

    queue-monitor length

  • Configure the switch to enable packet sampling of LANZ traffic

    Configure the switch to enable packet sampling of LANZ traffic

    queue-monitor length mirror

  • This command configures a port mirroring session to truncate mirrored packets, retaining only the first 128-192 bytes.

    monitor session truncate

  • Packet truncation can be used to prevent ___ of a monitor session’s destination port. It helps control the utilization of the Mirror CoPP. 

    oversubscription

  • packet ___ applies to the mirroring session as a whole, and cannot be applied to individual source ports.

    truncation

  • On Sand, the size of truncated packets can be set to either ___ or ___ bytes.

    On Sand, the size of truncated packets can be set to either ___ or ___ bytes.

    128, 192

  • On Strata/Alta, the number of bytes to be retained when truncating packets is fixed at ___

    160