show vlan brief
Displays a summary of all VLANs configured on the switch, including VLAN ID, name, status, and ports, used to quickly verify VLAN configuration and port assignments.
show vlan briefWhen to Use This Command
- After creating VLANs, verify they exist and are active before assigning ports.
- Troubleshoot connectivity issues by checking if a port is in the correct VLAN.
- Audit switch configuration to ensure only expected VLANs are present.
- Quickly identify which ports are in the default VLAN (VLAN 1) for security review.
Command Examples
Basic VLAN summary
show vlan briefVLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4
Fa0/5, Fa0/6, Fa0/7, Fa0/8
10 Sales active Fa0/9, Fa0/10, Fa0/11
20 Engineering active Fa0/12, Fa0/13, Fa0/14
30 Management active Fa0/15
1002 fddi-default act/unsup
1003 token-ring-default act/unsup
1004 fddinet-default act/unsup
1005 trnet-default act/unsupVLAN: VLAN ID number. Name: Descriptive name configured for the VLAN. Status: 'active' means VLAN is operational; 'act/unsup' for default VLANs not supported on this platform. Ports: Interfaces assigned to the VLAN. Note that VLANs 1002-1005 are default VLANs for legacy media types and are typically not used.
VLAN summary with only user-defined VLANs
show vlan brief | exclude fddi|token|trnetVLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4
Fa0/5, Fa0/6, Fa0/7, Fa0/8
10 Sales active Fa0/9, Fa0/10, Fa0/11
20 Engineering active Fa0/12, Fa0/13, Fa0/14
30 Management active Fa0/15Using the 'exclude' filter removes the default VLANs (1002-1005) from the output, making it easier to focus on user-created VLANs. The output shows only VLANs 1, 10, 20, and 30 with their respective ports.
Understanding the Output
The 'show vlan brief' command outputs a table with four columns: VLAN, Name, Status, and Ports. The VLAN column lists the VLAN ID (1-4094). The Name column shows the VLAN name (default is 'default' for VLAN 1). The Status column indicates whether the VLAN is active ('active') or suspended ('suspend'). VLANs with status 'act/unsup' are default VLANs for legacy technologies (FDDI, Token Ring) that are not supported on modern switches. The Ports column lists all access ports assigned to that VLAN, with multiple lines if needed. A port not listed in any VLAN row is likely in VLAN 1 by default. If a port is missing from its expected VLAN, check if it is in trunk mode or if the VLAN is deleted. Good practice: ensure only necessary VLANs are active; unused VLANs should be deleted for security. Watch for VLANs with status 'suspended' or 'act/unsup' as they may cause unexpected behavior.
CCNA Exam Tips
CCNA exam tip: The 'show vlan brief' command does not show trunk ports; use 'show interfaces trunk' for trunk information.
CCNA exam tip: VLAN 1 is the default VLAN and cannot be deleted, but you can change its name.
CCNA exam tip: The status 'act/unsup' appears for VLANs 1002-1005; these are not supported on modern switches and can be ignored.
CCNA exam tip: If a port is not listed under any VLAN, it is in VLAN 1 by default unless it is a trunk port.
Common Mistakes
Mistake 1: Assuming 'show vlan brief' shows all ports including trunk ports; trunk ports are not displayed here.
Mistake 2: Forgetting that VLAN 1 is always present and cannot be removed; attempting to delete it will fail.
Mistake 3: Misinterpreting 'act/unsup' as a problem; these are normal for default VLANs 1002-1005.
Related Commands
show interfaces trunk
Displays trunk interface status, allowed VLANs, and pruning information for all trunk ports on a Cisco switch, used to verify trunking configuration and VLAN membership.
show vlan
Displays the current VLAN configuration on the switch, including VLAN IDs, names, status, and ports assigned to each VLAN, used to verify VLAN creation and port assignments.
Practice for the CCNA 200-301
Test your knowledge with hundreds of CCNA practice questions covering all exam domains.
Practice CCNA Questions