DHCPPrivileged EXEC

show ip dhcp binding

Displays the current DHCP binding table, showing which IP addresses have been leased to clients, along with their MAC addresses, lease expiration, and type of binding.

Syntax·Privileged EXEC
show ip dhcp binding

When to Use This Command

  • Verify which IP addresses have been assigned to specific devices on the network.
  • Troubleshoot IP address conflicts by checking if an IP is already leased.
  • Monitor DHCP pool utilization to see how many addresses are in use.
  • Identify the MAC address of a device that has been assigned a particular IP.

Command Examples

Basic DHCP Binding Display

show ip dhcp binding
Bindings from all pools not associated with VRF:
IP address          Client-ID/              Lease expiration        Type
                     Hardware address
192.168.1.10         0063.6973.636f.2d30.    Mar 01 2025 12:00 PM   Automatic
                     3030.302e.6162.6364.
                     2e65.6667.68
192.168.1.11         0100.1a2b.3c4d.5e       Mar 02 2025 06:00 AM   Automatic
192.168.1.12         010a.0b0c.0d0e.0f       Mar 01 2025 08:30 PM   Automatic

The output shows three DHCP bindings. The first column is the IP address leased. The second column shows the client identifier (Client-ID) or hardware address (MAC). For Cisco devices, the Client-ID is often the MAC address prefixed with 01. The third column is the lease expiration date and time. The fourth column indicates the type of binding: 'Automatic' means the address was dynamically assigned.

Binding with Manual (Static) Entry

show ip dhcp binding
Bindings from all pools not associated with VRF:
IP address          Client-ID/              Lease expiration        Type
                     Hardware address
10.0.0.5            0100.1122.3344.55       Infinite                Manual
10.0.0.10           0100.aabb.ccdd.ee       Mar 03 2025 10:00 AM   Automatic

This example includes a manual binding (static DHCP assignment) for 10.0.0.5, which shows 'Infinite' lease expiration and type 'Manual'. The second binding is automatic with a finite lease. Manual bindings are configured with 'ip dhcp pool' and 'host' commands.

Understanding the Output

The output lists all IP addresses currently leased by the DHCP server. Each row corresponds to a binding. The 'IP address' column shows the leased IP. The 'Client-ID/Hardware address' column displays the client identifier, which is typically the MAC address in hexadecimal format, often preceded by '01' for Ethernet. The 'Lease expiration' column shows when the lease will expire; 'Infinite' indicates a static binding. The 'Type' column indicates whether the binding was assigned automatically (dynamic) or manually (static). In a real network, you use this command to verify that devices are receiving IPs from the correct pool, to identify rogue devices by MAC, or to check if the pool is exhausted. A healthy output shows a mix of active leases with future expiration times; if many leases are expiring soon or are 'Infinite', it may indicate misconfiguration. Watch for duplicate IPs (should not occur) or unexpected MAC addresses that could indicate unauthorized devices.

CCNA Exam Tips

1.

CCNA exam may ask you to identify the MAC address of a device given its IP from the binding table.

2.

Remember that 'Client-ID' can be different from the MAC address; Cisco devices often use a longer string.

3.

Know that 'Infinite' lease expiration indicates a manual (static) binding, not a dynamic one.

4.

The 'Type' field distinguishes between Automatic (dynamic) and Manual (static) bindings.

Common Mistakes

Confusing the Client-ID with the MAC address; the Client-ID may include a prefix like '01'.

Assuming all bindings are dynamic; forgetting that manual bindings also appear with 'Infinite' lease.

Misinterpreting the lease expiration format; it shows month, day, year, and time in AM/PM.

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