Owner's Manual

830 | Appendix C. Troubleshooting
NETGEAR 8800 User Manual
Troubleshooting Checklists
This section provides simple troubleshooting checklists for Layer 1, Layer 2, and Layer 3.
The commands and recommendations described are applicable to both IPv4 and IPv6
environments unless otherwise specified. If more detailed information about a topic is
available, you are referred to the applicable section in this appendix.
Layer 1
When troubleshooting Layer 1 issues, verify:
• The installation of cables and connectors.
• The behavior of LED status lights. For additional information about LEDs, see LEDs on
page 833.
• That the port is enabled, the link status is active, and speed and duplex parameters match
the port settings at the other end of the cable.
To display the configuration of one or more ports, use the show ports configuration
command.
• That the packets are being received and transmitted.
To display the number of packets being received and transmitted, use the show ports
{<port_list> | stack-ports <stacking-port-list>} statistics {no-refresh}
command.
• That there are no packet errors.
To display packet error statistics, use the following commands:
• show ports {<port_list> | stack-ports <stacking-port-list>} rxerrors
{no-refresh}
—Displays receive error statistics
• show ports {<port_list> | stack-ports <stacking-port-list>} txerrors
{no-refresh}
—Displays transmit error statistics
• show ports {mgmt | <port_list>} collisions {no-refresh}—Displays collision
statistics
Layer 2
When troubleshooting Layer 2 issues, verify:
• That the MAC addresses are learned, in the correct Virtual LAN (VLAN), and are not
blackhole entries.
To display FDB entries, use the show fdb command.
• Your VLAN configuration, including the VLAN tag, ports in the VLAN, and whether or not
the ports are tagged.