Description
This article describes steps to take when ports do not update properly with the current VLAN information. Symptoms include:
- The message "unable to read VLAN" appears when the Model Configuration is opened for a device.
- Current VLAN is wrong or blank in the Port View for the device
Scope
Version: 8.x
Solution
VLANs are read using various methods depending upon the device: SNMP, CLI or REST API. Verify the following:
1. SNMP and CLI credentials are correct (under switch's model configuration Credentials tab, click Validate Credentials).
If SNMP credentials fail, see related KB article below.
If CLI credentials fail, see related KB article below.
If using SNMP v3: Switches using SNMP v3 must have unique Engine IDs (msgAuthoritativeEngineID). They are used to identify the device. If multiple switches have the same Engine ID, sporadic unpredictable results may occur.
2. If Cisco switch, verify the CLI banner is appropriate. See related KB article below.
3. If running older code, check for any related fixes in newer code listed under the Enhancements and Addressed Issues section of the Release Notes in the Fortinet Document Library.
If the device was originally showing "?" when first added to Topology, then modeled using an Existing Device Mapping, there may be some mappings that are not complete. Further investigation would be required in this case. See Debugging below.
Debug
If behavior persists, further debugging may be required. Contact Support for assistance.
Open a support ticket and provide the following information:
- Problem description
- Did the VLAN read work previously for this device? If so, were any recent changes made (firmware upgrades, etc)?
- Screen capture of behavior
- Screen capture of the device's Element tab in Network Devices > Topology
- Screen capture of Help > About
Related Articles
Technical Note: Troubleshooting CLI credential failure
Technical Note: Troubleshooting SNMP communication issues
Technical Tip: Issues using '#' character in CLI banner
