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5. Appendix A: Troubleshooting 5.1.Troubleshooting Chart
Troubleshooting Chart
Symptom Action
Cannot connect
using Telnet, Web
browser, or SNMP
software
• Be sure you have configured the agent with a valid IP
address, subnet mask and default gateway (Layer 2).
• Check that you have a valid network connection to
the switch and that the port you are using has not
been disabled.
• Check network cabling between the management
station and the switch.
• If you cannot connect using Telnet, there may already
be four active sessions. Try connecting again at a
later time.
Cannot access the
onboard
configuration
program via a serial
port connection
• Be sure you have set the terminal emulator program
to VT100 compatible, 8 data bits, 1 stop bit, no parity,
and 19200 bps.
• Check that the null-modem serial cable conforms to
the pin-out connections provided in Appendix B.
Forgot or lost the
password
• Reinstall the switch firmware as described on the next
page.
5.2.Upgrading Firmware via the Serial Port
You can upgrade system firmware by connecting your computer to the serial port on the
switch and using a console interface package that supports the Xmodem protocol. (See
“Required Connections” on chapter 1.)
1. Restart the system by using the Restart System command, or by pulling out the
power cord to reset the power, waiting five seconds, and plugging it back in.
2. When the system initialization screen appears as shown below, press “D” to
download system firmware, and then indicate the code type (<r> Runtime image or
<d> Diagnostic image).