Managing IP Pools and DHCP Leases in MikroTik

IP Pool and DHCP Management on MikroTik

Effective DHCP management keeps your network running smoothly. This post covers routine DHCP administration tasks: managing pools, cleaning stale leases, tracking clients, and handling IP conflicts.

Reviewing Pool Utilization

/ip pool used print
/ip pool print

Compare used against the pool's range to gauge utilization. A pool nearing exhaustion means some clients will fail to get IPs.

Listing All Active Leases

/ip dhcp-server lease print

Add status filters:

/ip dhcp-server lease print where status=bound      # active leases
/ip dhcp-server lease print where status=waiting    # expiring/pending

Clearing Stale Leases

Old devices leave stale leases in your table. Manual cleanup:

/ip dhcp-server lease remove [find status=waiting]
/ip dhcp-server lease remove [find last-seen>1d]

Or adjust lease time so stale entries expire faster:

/ip dhcp-server network set [find] lease-time=12h

Converting a Dynamic Lease to Static

When a device should always get the same IP:

/ip dhcp-server lease make-static [find address=192.168.10.55]

This locks that device's MAC to that IP. Alternatively, add manually:

/ip dhcp-server lease add address=192.168.10.55 mac-address=AA:BB:CC:DD:EE:FF server=dhcp1

Searching for a Device by MAC

/ip dhcp-server lease print where mac-address="AA:BB:CC:DD:EE:FF"

Useful when a user reports connectivity problems — find their IP from MAC address.

Finding Duplicate IPs

IP conflicts cause mysterious connectivity problems. Use ARP to find duplicates:

/ip arp print

If two MACs share the same IP, you have a conflict. Check for rogue DHCP servers or static IP assignments overlapping with the pool.

Expanding the Pool When Running Low

/ip pool set dhcp_pool ranges=192.168.10.10-192.168.10.250

Or add a second pool range:

/ip pool add name=dhcp_pool2 ranges=192.168.20.10-192.168.20.200
/ip dhcp-server set dhcp1 address-pool=dhcp_pool,dhcp_pool2

DHCP Lease Notification Script

Get notified when a new device joins:

/system script add name=new-lease-alert source={
  :local mac [/ip dhcp-server lease get [find where dynamic=yes] mac-address]
  /tool e-mail send to=admin@example.com subject=("New device: " . $mac) body=($mac . " got IP")
}
/ip dhcp-server set dhcp1 lease-script=new-lease-alert

Blocking Specific Devices from DHCP

Add a static lease with an IP outside your pool to effectively block a MAC from getting an IP:

/ip dhcp-server lease add mac-address=BA:D0:FF:EN:DE:D0 address=192.168.10.254 server=dhcp1 comment=blocked

Or use the /ip dhcp-server lease make-permanent approach and then add a firewall rule blocking that IP.

Clean DHCP management prevents mysterious "no internet" calls and IP conflict incidents. Make lease table review part of your monthly maintenance routine.