• If the default severity value is in effect, all messages that have severities greater than the default value are
passed to syslog. For example, if the default severity is "debug," all messages that have severities greater
than debug are passed to syslog.
• There is a limit of six syslog servers. All syslog servers are sent the same messages using the same filter
parameters. An error is generated for an attempt to add more than six syslog servers.
Diagnostic tools
Port auto-negotiation
When a link LED does not light (indicating loss of link between two devices), the most common reason is a failure
of port auto-negotiation between the connecting ports. If a link LED fails to light when you connect the switch to a
port on another device, do the following:
Procedure
1. Ensure that the switch port and the port on the attached end-node are both set to Auto mode.
2. If the attached end-node does not have an Auto mode setting, you must manually configure the switch port to
the same setting as the end-node port.
Ping and link tests
The ping test and the link test are point-to-point tests between your switch and another IEEE 802.3-compliant
device on your network. These tests can tell you whether the switch is communicating properly with another
device.
NOTE:
To respond to a ping test or a link test, the device you are trying to reach must be IEEE 802.3-
compliant.
Ping test
A test of the path between the switch and another device on the same or another IP network that can respond to
IP packets (ICMP Echo Requests). To use the ping (or traceroute) command with host names or fully
qualified domain names, see DNS resolver on page 544.
Link test
A test of the connection between the switch and a designated network device on the same LAN (or VLAN, if
configured). During the link test, IEEE 802.2 test packets are sent to the designated network device in the same
VLAN or broadcast domain. The remote device must be able to respond with an 802.2 Test Response Packet.
Executing ping or link tests (WebAgent)
To start a ping or link test in the WebAgent:
1. In the navigation pane, click Troubleshooting.
2. Click Ping/Link Test.
3. Click Start.
4. To halt a link or ping test before it concludes, click Stop.
Chapter 13 Troubleshooting 527
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