How to Configure an Antminer S19 or S21: Complete 2026 Tutorial

The Antminer S19 XP and S21 are the most widely deployed Bitcoin mining machines in the world. Whether you've just received your first ASIC or you're adding a machine to your existing farm, this tutorial walks you through everything from unboxing to the first hash — then guides you through advanced optimizations.

Every step includes the exact values to enter. If you're completely new to mining, start with our beginner's guide to Bitcoin mining in 2026 to understand the basics.

Before You Start: Essential Checks

Electrical Installation

This is the most critical point. A poorly connected ASIC can cause a fire or damage your electrical system.

| Model | Power draw | Minimum circuit | Breaker | Wire gauge | |-------|-----------|----------------|---------|-----------| | S19 XP (141 TH/s) | 3,010 W | Dedicated 220V | 20A | 10 AWG | | S19 Pro (110 TH/s) | 3,245 W | Dedicated 220V | 20A | 10 AWG | | S21 (200 TH/s) | 3,500 W | Dedicated 220V | 20A | 10 AWG | | S21 Hydro (335 TH/s) | 5,360 W | Dedicated 220V | 30A | 8 AWG |

Non-negotiable rules:

Never plug an ASIC into a standard power strip or extension cord
One dedicated circuit per machine (or two machines max on a 30A circuit)
Dedicated breaker at the electrical panel
Verify your electrical service can handle the total load

Network

One Ethernet cable (RJ45, Cat5e minimum) per machine
A router or switch with enough ports
Stable internet connection (bandwidth requirement is low: ~100 KB/s per ASIC)
Do not use WiFi: latency and disconnections reduce your revenue

Environment

Ambient temperature: 60-85°F (15-30°C) ideally. Above 95°F, the machine overheats and reduces hashrate.
Ventilation: an S21 produces ~3,500 W of heat — equivalent to 3 space heaters. Hot air must be exhausted.
Noise: 75-80 dB. Impossible to live or work nearby without protection. Plan a separate room or building.
Dust: a dusty environment will clog fans within weeks. Filter incoming air if possible.

Step 1: Physical Setup

Unboxing and Inspection

Before connecting power, inspect the machine:

Check for visible shipping damage
Gently shake the ASIC — no rattling sounds should be heard
Verify that fans spin freely by hand

Connecting

Place the ASIC on a stable, flat surface with at least 12 inches (30 cm) of clearance front and back for airflow
Connect the power supply:
- S21: single PSU, single cable
- S19 XP/Pro: two PSUs. Plug in both — the machine won't run properly on just one
Connect the Ethernet cable to your router or switch
Power on

The machine starts with loud fan noise — that's normal. Wait 2-3 minutes for the system to initialize and obtain an IP address.

Step 2: Find Your ASIC's IP Address

The machine automatically gets an IP address via DHCP. Three methods to find it:

Method 1: Router Admin Panel

Open your browser and go to 192.168.1.1 (or 192.168.0.1 depending on your router)
Log into the admin interface
Find the connected devices list (usually under "Network" or "DHCP")
Look for a device named "Antminer" — note its IP address (e.g., 192.168.1.105)

Method 2: Network Scan

On Windows: download Advanced IP Scanner and scan your local network.

On Mac/Linux: open a terminal and type:

nmap -sn 192.168.1.0/24

Look for an entry with "Antminer" or manufacturer "Bitmain."

Method 3: IP Report Button

On some models (especially S19), a small button on the control panel triggers an audible announcement of the IP address. Press once and listen.

Step 3: Access the Web Interface

Open your browser (Chrome, Firefox, Safari)
In the address bar, type your ASIC's IP: http://192.168.1.105
Log in with the default credentials:
- Username: root
- Password: root

⚠️ Security: immediately change the default password. Go to System > Change Password. An ASIC with default credentials is vulnerable to attacks on your local network (someone could redirect your hashrate to their own pool).

Step 4: Configure Your Mining Pool

This is the core of the setup. Navigate to Miner Configuration > Mining Pool Settings.

You'll see 3 pool slots (Pool 1, Pool 2, Pool 3). Here's the recommended configuration:

Pool 1 — Minent Proxy (Primary)

URL: stratum+tcp://proxy.minent.eu:3333
Worker: the worker name provided by Minent when you register (format: account.machine_name)
Password: x

Using Minent as Pool 1, your hashrate is automatically routed to the most profitable pool. The proxy handles pool switching, failover, and real-time optimization. For more on this approach, read our article on smart pool switching.

Pool 2 — Direct Failover (Backup)

In case the proxy is temporarily unavailable:

URL: stratum+tcp://btc.f2pool.com:3333
Worker: your_wallet_address.machine_name
Password: x

Pool 3 — Second Failover

URL: stratum+tcp://stratum.antpool.com:3333
Worker: your_wallet_address.machine_name
Password: x

Click Save & Apply. The machine will restart its mining process (no physical reboot) and connect to Pool 1.

For help choosing the best pools for your failover, see our 2026 Bitcoin mining pool comparison.

Step 5: Verify Mining is Working

Wait 5-10 minutes, then go to Miner Status (or Dashboard depending on firmware version).

Metrics to Check

| Metric | Expected (S21) | Expected (S19 XP) | Problem if... | |--------|----------------|-------------------|---------------| | Hash Rate (RT) | ~200 TH/s | ~141 TH/s | < 80% of rated | | Hash Rate (avg) | ~200 TH/s | ~141 TH/s | Gradual decline | | Accepted shares | Increasing steadily | Increasing steadily | Stagnant | | Rejected | < 1% | < 1% | > 2% | | HW Errors | 0 | 0 | > 0 = hardware issue | | Chip temperature | 55-75°C | 55-75°C | > 85°C = throttling | | Fan speed | 3000-6000 RPM | 3000-6000 RPM | 0 = dead fan |

If everything looks good, congratulations — your ASIC is mining Bitcoin. If you're using Minent, your metrics are also visible on the online dashboard from your phone or computer.

Step 6: Performance Modes

Antminers offer several operating modes. In Miner Configuration > Performance Mode:

Normal Mode

Hashrate: 100% of rated
Power: 100% of rated
Recommended for most situations

Low Power Mode

Hashrate: ~80% of rated
Power: ~60-70% of rated
Best efficiency (J/TH) — ideal if your electricity is expensive
Also reduces noise and heat

High Performance Mode (Turbo)

Hashrate: ~110% of rated
Power: ~120% of rated
More heat, more noise, more wear
Only use if your cooling and electrical circuit can handle it

Our recommendation: Low Power Mode is often the best choice for maximizing profit per kWh. Unless your electricity is very cheap (< $0.04/kWh), in which case Normal Mode maximizes gross revenue.

Advanced Option: Braiins OS

Braiins OS is an open-source alternative firmware for Antminers. It replaces the Bitmain factory firmware and offers advanced features:

Auto-tuning: the firmware automatically adjusts frequency and voltage for each chip to maximize efficiency
Better efficiency: typically 5-10% reduction in power consumption at equivalent hashrate
Fine-grained control: you can set a wattage limit and let the firmware optimize hashrate within that envelope

Installing Braiins OS

Go to braiins.com and download the firmware for your model
In the Antminer interface, go to System > Firmware Upgrade
Select the downloaded file and click Flash
Wait 5-10 minutes — do not unplug the machine during the update
Reconnect (the IP may change) with credentials root / root

⚠️ Warning: installing Braiins OS voids Bitmain's warranty. It's irreversible on some models (returning to factory firmware isn't always possible). Proceed with full awareness.

Pool Configuration Under Braiins OS

The interface is different but the concept is the same:

Go to Configuration > Pool Groups
Add a group with your pools (Minent proxy first, failover pools next)
Under Tuning, enable auto-tuning and set your power consumption target
Click Save & Apply

Troubleshooting Common Issues

Hashrate is Zero

| Cause | Check | Solution | |-------|-------|---------| | Incorrect pool URL | Verify exact syntax | Fix the URL (watch for typos) | | No network connection | Is the Ethernet cable plugged in? Network LED lit? | Replace cable, check switch port | | Firewall blocking | Is port 3333 open? | Open the port in your router | | ASIC still booting | Wait 5-10 min after power-on | Be patient |

High Rejected Shares (> 2%)

High latency: choose a closer pool server or use a proxy that optimizes routing
Outdated firmware: update to the latest version
Unstable network: replace the Ethernet cable, check the switch

Temperature Too High (> 85°C / 185°F)

Verify fans are working (speed > 0 RPM)
Improve room ventilation (exhaust fan, AC)
Clean dust from heatsinks and fans
Lower ambient temperature or switch to Low Power Mode

Frequent Reboots

Unstable power: check your electrical circuit (stable voltage, no micro-outages)
Overheating: see above
Buggy firmware: try updating or reinstalling firmware
Faulty PSU: if only one PSU is connected on an S19, the machine will reboot in a loop

"Stratum Connection Failed"

Pool server is down → check pool status page
Your ISP blocks the port → try an alternate port (e.g., 443 instead of 3333)
DNS resolution failed → try the server's direct IP address

Regular Maintenance

To keep your machines performing long-term:

Monthly: check metrics (hashrate, temperature, rejects) on your dashboard
Quarterly: clean fans and air filters (compressed air)
Every 6 months: visual inspection of power connectors (signs of heat damage?)
Each firmware update: review release notes before flashing

Looking for a new or used ASIC? Browse our machine catalog on minent.eu.

Conclusion

Configuring an Antminer is straightforward when you follow the steps in order. The essentials: secure your electrical installation, configure pools correctly (with failover), and monitor performance over time. A proxy like Minent significantly simplifies daily management by centralizing monitoring and optimization.

Machine configured? Create your Minent account to start optimizing your revenue automatically — it's free and takes 2 minutes.