DHCP
DHCP is a router handing out addresses for a period of time. Handy for a laptop, not for a miner: after a reboot the web interface turns up at a different address.
What DHCP is
The router keeps a stock of addresses and leases them to devices. A lease has a term, usually from an hour to a day. Until the term runs out a device gets the same address, and after a router reboot or a long shutdown it can get another one.
Bitmain asics come set to DHCP out of the box, so the first login to the interface goes through a network scanner or through the client list in the router. How to find a miner on the network is covered on the page about the IP address.
The trouble starts with the second asic. When addresses drift, you work out who is who from scratch every time, and a monitoring system loses the host. On ten asics that is already half an hour of work instead of one minute.
There are two cures. A static address is written into the asic itself, and the router no longer takes part in it. A MAC reservation is made on the router, so the miner stays on DHCP and always gets the same address. Farms more often take the reservation: the address map sits in one place instead of twenty web interfaces.
Quick reference table
| What it does | hands out addresses for a lease term |
| Lease term | usually from an hour to a day |
| On Bitmain out of the box | enabled |
| Downside for a miner | the address can change |
| How to pin an address | static in the asic or a reservation on the router |
How to set it up
Collect the MAC addresses of the asics, which are printed on the case and visible in the interface. That is the key for a reservation.
Set up a reservation for every MAC on the router and hand out addresses in order, by rack position number for example. Then the worker name, the address and the physical spot line up, and hunting for an asic stops being a quest.
If the router cannot do reservations, write a static address into the asic, but be sure to keep it outside the DHCP range. Otherwise the router will one day give that same address to a laptop, and both lose the link.
A setup example
The DHCP range on the router is narrowed to addresses from 100 to 199, while the asics get reservations from 10 to 40 by rack position number. Phones and laptops take addresses from the common range and never cross with the equipment. A new asic gets its address by its own number right away, and it goes into monitoring as a single line.
Related terms
Where to go next on the site
Hardware
- ASIC Miner knowledge base
Software
- HashCore Toolkit firmware
- Software firmware
Questions and answers
Which is better, static or a reservation
On one or two asics there is no difference. From three up a reservation is handier: all the addresses are visible in one list on the router.
Why did the asic disappear after a router reboot
Most likely it got a different address out of the range. That is exactly the reason miner addresses get pinned down.
Should DHCP be turned off entirely
No, phones and laptops need it. Narrowing its range and moving the equipment outside that range is enough.
How the terms connect
Every link in the chain is clickable. Orange marks where you are now.
Looking for an ASIC miner
The catalog holds 212 models. You can compare them by hashrate and by joules per terahash, then plug your own rate into the calculator and see what stays in your pocket.
Page written and checked by Denys Klimchuk. Updated .