An exclude is an address Lattice dhcpd must never Offer. Microsoft’s exclusion range is the same idea. Gateways and VIPs belong here even if Microsoft “just knew” not to hand out .1.
Reservations: reservations. First subnet: first-subnet.
1. Why the gateway is not automatic
Microsoft scopes often start the range at .10 and people never exclude .1. Lattice will Offer any address in a pool that is not reserved, excluded, leased, or quarantined. If the pool includes .1, a laptop can steal the router.
Day one on every DHCP subnet: Add address → Don’t offer the gateway (single IP: leave end blank). Repeat for HSRP/VRRP/anycast VIPs, PXE helpers that are not DHCP clients, and holes your monitoring already uses.
Work → Gateways lists subnets whose gateway is not excluded (and not already reserved/assigned). That is a checklist, not a page of errors.
2. Exclude vs reservation vs pool
| Object | dhcpd | License |
|---|---|---|
| Exclude | Will not Offer | Does not count |
| Reservation | Only that client | Counts (managed IP) |
| Pool | Dynamic Offer | Live leases count |
Do not exclude a printer you still want on DHCP — reserve it. Do not reserve the gateway.
Shrinking a pool (new range is a subset) is allowed. Growing is refused. Live leases outside the new range renew until they expire, then no Offer. The console shows the impact before you save (GET /api/v1/pools/{id}/impact).
3. Click path
Subnet map or Add address → Don’t offer. Start IP required. End IP optional (blank = one address).
There is no “used” checkbox. Exclude means dhcpd will never Offer that address. Cataloged statics are assignments; DHCP clients are reservations.