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This chapter contains a list of known problems and suggested solutions. It covers the following topics:
If you have a problem that is not listed here and you cannot solve it, please contact your local technical support representative.
The Web browser cannot access the Switch over the network. Check that:
The Web browser cannot access the Switch over a serial link from a management station running Windows® 95. You must access the Switch using the 3Com Serial Web Utility (SLIP Driver); see "Serial Web Utility".
The Web browser can no longer access the Switch over the network. Check that:
If there is still a problem, try accessing the Switch through a different port. If you can now access the Switch, a problem may have occurred with the original port. Contact your supplier for further advice.
Some of the web interface is not displayed in the Web browser after downloading. This is probably due to large amounts of traffic on the network. Either reload the web interface page, or click in the part of the interface that has not displayed and select the reload frame option in your Web browser.
The web interface takes time to respond to commands, and "Document contains no data" messages are displayed. Too many users are accessing the web interface at the same time. We recommend that you allow only three users to access the interface.
"URL not found" messages are displayed when the Help or Documentation icons are clicked. The web interface cannot access the online help or online documentation files. For more information, see "Installing Online Help and Documentation".
"URL not found" messages are displayed when the 3Com Library, 3Com Contacts or 3Com Support icons are clicked. Your management workstation cannot access the World Wide Web. Contact your network administrator.
The units in the Unit icon are not displayed in the order that they are stacked. If you have a stack of two units connected back-to-back, the unit with the lowest MAC address is displayed at the bottom of the Unit icon. If you have a stack of up to four units connected using a Matrix Module, the order of units in the Unit icon follows the ports on the Matrix Module - the unit connected to the Unit 1 port is displayed at the bottom of the Unit icon, the unit connected to the Unit 2 port is displayed above that unit, and so on.
The Switch graphic shown on the web interface does not refresh automatically. You may need to make a small change to your Web browser so that it always downloads the latest version of a web page from the web interface. To do this for Netscape Navigator Version 3.0:
1 . Start Netscape Navigator.
2 . From the Options menu, select Network Preferences.
3 . The Preferences dialog box appears.
4 . Check the Every Time checkbox.
5 . Click OK.
To do this for Microsoft Internet Explorer Version 3.0:
1 . Start Microsoft Internet Explorer.
2 . From the View menu, select Options.
3 . The Options dialog box appears.
4 . Select the Advanced tab, and in the Advanced property sheet click Settings.
5 . Check the Every visit to the page checkbox.
6 . Click OK.
You forget your password while logged out of the web interface and cannot log in. Ask another user with Security access level to log in and initialize the Switch. This returns the Switch to its default (factory) settings, including any password information. For more information, see "Initializing All the Units in the Stack".
In the case where no-one knows a password for a user with Security access level, the Switch needs to be sent back to your supplier so that it can be returned to 3Com.
A management software upgrade has failed, and you can no longer manage the Switch using the web interface. Try accessing the command line interface and upgrading the Switch again. If that is not possible, use the Management Software Upgrade Utility to upgrade it through the console port. For more information about the Management Software Upgrade Utility, see "Using the Upgrade Utility".
I
f the Switch is stacked, separate each Switch from the stack and use the Management Software Upgrade Utility to upgrade each Switch individually.
The terminal or terminal emulator cannot access the Switch. Check that:
The auto-configuration feature of the Switch only works with line speeds from 1200 to 19,200 baud.
If the login sequence still does not display, reset the Switch. For more information, see "Resetting All the Units in the Stack". If this does not work, initialize the Switch. For more information, see "Initializing All the Units in the Stack".
The terminal or terminal emulator can no longer access the Switch over the network. Check that:
If there is still a problem, try accessing the stack through a different port. If you can now access the Switch, a problem may have occurred with the original port. Contact your supplier for further advice.
You forget your password and cannot log in. Ask another user with Security access level to log in and initialize the Switch. This returns the Switch to its default (factory) settings, including any password information. For more information, see "Initializing All the Units in the Stack".
In the case where no-one knows a password for a user with Security access level, the Switch needs to be sent back to your supplier so that it can be returned to 3Com.
A management software upgrade has failed, and you can no longer manage the Switch using the command line interface. Try accessing the command line interface and upgrading the Switch again. If that is not possible, use the Management Software Upgrade Utility to upgrade it through the console port. For more information about the Management Software Upgrade Utility, see "Using the Upgrade Utility".
If the Switch is stacked, separate each Switch from the stack and use the Management Software Upgrade Utility to upgrade each Switch individually.
The SNMP Network Management Software cannot access the Switch. Check that:
Traps are not received by the SNMP Network Management software. Check that the IP information of the SNMP Network Management software is correctly recorded by the Switch.
The SNMP Network Management software can no longer access the Switch. Check that:
If there is still a problem, try accessing the Switch through a different port. If you can now access the Switch, a problem may have occurred with the original port. Contact your supplier for further advice.
You cannot connect to the web interface of the Switch.
Check that:
You can change some of the settings for the management workstation using the Advanced Configuration Parameters dialog box. To display this, select the Serial Web Setup program item in the Serial Web program group.
An error occurs when the utility attempts to connect through the serial port of the PC. The serial port being used is not the same as the serial port specified in the upgrade command. Retry the command ensuring that you specify a value of `1' or `2' for the serial port.
An error occurs when the utility attempts to communicate with the Switch. There could be a number of reasons for this:
Retry the command ensuring that you follow all the steps.
An error occurs when the utility attempts to open the management software file for reading. There could be two reasons for this:
The error message USAGE: update [-c comport] filename is displayed. You are not specifying the correct number of parameters for the upgrade command. Retry with the correct parameters.
An error occurs when the utility attempts to transfer the file. There could be a number of reasons for this:
You see network problems and a Packet LED is lit continuously due to constant collisions. You are using PACE-equipped devices and PACE is enabled at both ends of the link. PACE must only be enabled at one end of the Switch-device link. Disabling PACE for a port is described in "Configuring a Port".
You have added the Switch to an already busy network, and response times and traffic levels have increased. You may have added a group of users to one of the Switch ports via a hub, and not disabled half duplex flow control for the port. Disable half duplex flow control for all ports that are operating in half duplex and are connected to multiple devices using a hub. Disabling half duplex flow control is described in "Configuring a Port".
You have enabled auto-negotiation for a 10BASE-T/100BASE-TX port, and you are seeing a large number of late events on the port. The port connected to the Switch is not auto-negotiating and is operating in full duplex:
You have specified that an endstation generates traffic that has a high priority, but when it passes through the network this priority information is lost. The endstation is attached to a Switch port using an untagged VLAN connection, and the Switch is removing the priority information when it is forwarded to other untagged ports. To maintain the priority information, specify that all untagged Switch ports use 802.1Q tagging.
You have placed two or more Switch units in a stack, and some ports have lost their VLAN allocations and been disabled. The Switch units had more than 16 VLANs defined between them, and these extra VLANs were removed when the units were stacked. If a port was allocated to one of these VLANs among others, it lost that particular VLAN allocation. If a port only belonged to removed VLANs, it lost all its VLAN allocations and was disabled. Re-enable the disabled ports, and place them in the remaining VLANs.
You have connected a Switch to a device using an 802.1Q tagged link, and you can no longer access the management software of the device or the devices connected to that device. You may have connected to a device that only supports 802.1Q tagged links and have not specified that VLAN 1 traffic uses 802.1Q tagging. Specify that VLAN 1 traffic is 802.1Q tagged, and try accessing the devices again.
You have connected an endstation that does not support IEEE 802.1Q to the Switch. When you specify that the Switch port belongs to an untagged VLAN, the endstation does not appear to be connected to that VLAN. The port may have been placed in the VLAN using 802.1Q tagging, and the Switch is only transmitting the VLAN traffic with 802.1Q tags. Remove the 802.1Q tagging for the port, and try again.
Your Switch should be operating as an IGMP Querier, but it is not sending query packets to the network. Check that:
You have attempted to upgrade several Switch units in a stack using TFTP, and one unit fails to upgrade. Take the following steps:
1 . Ensure that the unit has:
2 . If the unit has the IP address 0.0.0.0, ensure that the stack has a valid IP address that is in the same subnet as the TFTP server.
3 . Attempt the upgrade again.