How to Configure an Antminer S19 or S21: Step-by-Step Tutorial

The Antminer S19 XP and S21 are among the most popular Bitcoin mining machines on the market. This guide walks you through everything from unboxing to your first hash.

Before You Begin

Check Your Electrical Installation

• S19 XP: draws ~3000W — requires a dedicated 240V circuit rated for at least 15A
• S21: draws ~3500W — requires a dedicated 240V circuit rated for at least 20A
• Install a dedicated circuit breaker for each unit
• Never plug two ASICs into the same outlet or power strip

Prepare Your Network

• One Ethernet cable (RJ45) per machine
• A stable internet connection (bandwidth requirements are low: ~100 KB/s per ASIC)
• A router with enough ports, or a network switch

Prepare Your Environment

• Ideal ambient temperature: 15-30 deg C (59-86 deg F)
• Ventilation: plan for hot air extraction
• Noise: 75-80 dB, equivalent to an industrial vacuum cleaner

Step 1: Physical Setup

1. Place the ASIC on a stable, well-ventilated surface
2. Connect the power cables (the S21 has a single PSU, the S19 XP has two)
3. Plug the Ethernet cable into your router or switch
4. Power on the unit

The machine will start with a loud fan noise. Wait 2-3 minutes for it to obtain an IP address via DHCP.

Step 2: Find the IP Address

There are several methods:

Via Your Router

Log into your router's admin panel (often at 192.168.1.1 or 192.168.0.1) and look for the new device in the DHCP client list. It typically appears under the name "Antminer".

Via a Network Scan

Use a tool like Advanced IP Scanner (Windows) or nmap (Linux/Mac):

nmap -sn 192.168.1.0/24

Via the IP Report Button

On some models, press the small "IP Report" button on the control panel. The IP address is announced through the speaker.

Step 3: Access the Web Interface

1. Open your web browser
2. Enter the ASIC's IP address (e.g., 192.168.1.105)
3. Log in with the default credentials:
   • Username: root
   • Password: root

Important: Change the default password immediately under System > Change Password.

Step 4: Configure the Mining Pool

Navigate to Miner Configuration > Mining Pool Settings.

You will see 3 pool fields (Pool 1, Pool 2, Pool 3). Configure them as follows:

Pool 1 (Primary)

• URL: stratum+tcp://proxy.minent.eu:3333
• Worker: your worker name (assigned by the platform)
• Password: x

Pool 2 (Failover)

Set up a direct backup pool in case the proxy is unavailable:

• URL: stratum+tcp://btc.f2pool.com:3333
• Worker: your_wallet.worker_name
• Password: x

Pool 3 (Last Resort)

A third pool as a final fallback:

• URL: stratum+tcp://stratum.antpool.com:3333
• Worker: your_wallet.worker_name
• Password: x

Click Save & Apply.

Step 5: Verify That Mining Has Started

After a few minutes, go to the Miner Status page:

• Hash Rate (RT): real-time hashrate — should gradually climb toward the rated value
• Hash Rate (avg): the average — more reliable than real-time readings
• Accepted: number of accepted shares — should increase steadily
• Rejected: rejected shares — should remain near 0%
• HW Errors: hardware errors — should be at 0

If the hashrate has not started climbing after 10 minutes, check that:

• The pool URL is correct
• The Ethernet cable is properly connected
• The firmware is up to date

Step 6: Optimizations

Performance Mode

Under Miner Configuration, you can select:

• Normal: rated hashrate, standard power consumption
• Low Power: reduced hashrate, lower consumption (useful if your electricity is expensive)
• High Performance: boosted hashrate, higher consumption (watch the temperature closely)

Fan Speed

If the temperature exceeds 80 deg C (176 deg F), increase the fan speed under System > Fan Speed. A cooler ASIC is a more stable ASIC.

Firmware Updates

Check regularly for updates on the official Bitmain website. New firmware versions fix bugs and sometimes improve efficiency.

Common Troubleshooting

| Problem | Likely Cause | Solution | |---------|-------------|----------| | Hashrate at 0 | Incorrect pool URL | Verify the configuration | | High reject rate | Network latency | Choose a closer pool server | | High temperature | Insufficient ventilation | Improve airflow | | Frequent reboots | Unstable power supply | Check the electrical circuit | | "Stratum connection failed" | Pool down or firewall blocking | Test with a different pool |

Conclusion

Configuring an Antminer is straightforward once you know the steps. The essentials are to properly prepare your electrical installation, correctly configure your pools (with failover), and regularly monitor your machine's performance.