Users in a VLAN Cannot Communicate

Procedure

1. Check whether the interfaces connected to user terminals are in Up state.

   Run the display interface interface-type interface-number command in any view to check the status of the interfaces.

   • If the interface is Down, rectify the interface fault.

   • If the interface is Up, go to 2.

2. Check whether the IP addresses of user terminals are on the same network segment. If they are on different network segments, change the IP addresses of the user terminals to be on the same network segment. If the fault persists, go to 3.
3. Check whether the MAC address entry is correct.

   Run the display mac-address command on the Switch to check whether MAC addresses, interfaces, and VLANs in the learned MAC address entries are correct. If the learned MAC address entries are incorrect, run the undo mac-address mac-address vlan vlan-id command in the system view to delete MAC address entries so that the Switch can learn the correct MAC address entries.

   After the MAC address table is updated, check the MAC address entries again.

   • If the MAC address entries are incorrect, go to 4.
   • If the MAC address entries are correct, go to 5.

4. Check whether the VLAN is properly configured.

   Check the VLAN configuration according to the following table.

   Check Item	Method
   Whether the VLAN has been created	Run the display vlan vlan-id command in any view to check whether the VLAN has been created. If not, run the vlan command in the system view to create the VLAN.
   Whether the interfaces are added to the VLAN	Run the display vlan vlan-id command in any view to check whether the VLAN contains the interfaces. If not, add the interfaces to the VLAN. NOTE: If the interfaces are located on different switches, add the interfaces connecting the switches to the VLAN. The default type of an interface is Negotiation. You can run the port link-type command to change the link type of an interface. Add an access interface to the VLAN by using either of the following methods. Run the port default vlan command in the interface view, or run the port command in the VLAN view. Add a trunk interface to the VLAN. Run the port trunk allow-pass vlan command in the interface view. Add a hybrid interface to the VLAN by using either of the following methods. Run the port hybrid tagged vlan command in the interface view, or run the port hybrid untagged vlan command in the interface view.
   Whether connections between interfaces and user terminals are correct	Correctly connect user terminals to device interfaces.

   After the preceding operations, if the MAC address entries are correct, go to 5.

5. Check whether port isolation is configured.
   Run the interface interface-type interface-number command in the system view to enter the interface view, and then run the display this command to check whether port isolation is configured on the interface.

   • If port isolation is not configured, go to 6.
   • If port isolation is configured, run the undo port-isolate enable command on the interface to disable port isolation. If the fault persists, go to 6.

6. Check whether the correct static Address Resolution Protocol (ARP) entries are configured on the user terminals. If the static ARP entries are incorrect, modify them. Otherwise, go to 7.
7. Collect logs and alarms and contact technical support personnel.