How to Test Ping, DNS and Network Stability

Learn how to test Ping, DNS resolution, TCP ports, packet loss, routing, and long-term network stability for PECPool mining connections. This guide includes practical Windows and Linux commands and explains how to interpret the results when troubleshooting Offline workers, Pool Dead errors, stale shares, and unstable hashrate.

A stable network connection is essential for Bitcoin mining. An ASIC miner must continuously receive new mining jobs from PECPool and submit completed shares back to the stratum server.

A miner may remain powered on and display local hashrate even when its internet connection is unstable. During that time, shares may arrive late, be rejected, or fail to reach PECPool completely.

Network tests can help identify problems such as:

• High latency
• Packet loss
• DNS resolution failure
• Blocked stratum ports
• Incorrect routing
• Unstable internet service
• Frequent pool disconnections

This guide explains how to test Ping, DNS, TCP connectivity, packet loss, routing, and long-term network stability from Windows and Linux.

Why Network Stability Matters in Bitcoin Mining

Mining requires a continuous two-way connection:

1. PECPool sends a new Bitcoin mining job to the ASIC miner.
2. The miner performs SHA-256 calculations.
3. The miner submits qualifying shares to PECPool.
4. PECPool validates the submitted shares.
5. Accepted shares contribute to effective hashrate and mining rewards.

When the connection is delayed or interrupted:

• The miner may continue working on an outdated job.
• Shares may arrive after the job has changed.
• Stale or rejected shares may increase.
• The PECPool worker may become Offline.
• Pool-side hashrate may fall below local hashrate.
• The miner may repeatedly switch between Pool 1, Pool 2, and Pool 3.

Perform Tests from the Mining Network

Run network tests from a computer connected to the same router, internet connection, or gateway used by the ASIC miners.

A test from another city, mobile connection, office network, or remote server may produce different results because it uses a different internet route.

For the most relevant result:

• Connect the test computer to the same switch or router as the miners.
• Use the same internet provider.
• Test the exact PECPool hostname and port configured in the miners.
• Repeat the tests during the hours when the problem normally occurs.

Official PECPool Bitcoin Stratum Servers

Region	Server	Available Ports
Global	btc.pecpool.com	3333, 443, 25
United States	btc-us.pecpool.com	3333, 443, 25
Europe	btc-eu.pecpool.com	3333, 443, 25
Russia	btc-ru.pecpool.com	3333, 443, 25
Asia	btc-as.pecpool.com	8443, 443, 25
Iran	btc-ir.pecpool.com	8443, 443, 25
Iran Alternative	btc.pecpool.cc	8443, 443, 25

Always test the hostname and port currently configured in the miner.

What Does Ping Test?

Ping sends ICMP test packets to a destination and measures whether replies return.

A Ping test can provide information about:

• Basic network reachability
• Approximate round-trip latency
• Packet loss
• Large changes in response time

Ping is useful, but it does not directly test the stratum mining port.

A PECPool server may ignore Ping while still accepting normal stratum connections. Therefore, a failed Ping does not automatically mean that mining cannot connect.

Run a Ping Test in Windows

Open Command Prompt and enter:

ping btc-eu.pecpool.com

Windows normally sends four Ping requests and displays a result similar to:

Packets: Sent = 4, Received = 4, Lost = 0
Minimum = 48ms, Maximum = 55ms, Average = 51ms

For a longer test, use:

ping btc-eu.pecpool.com -n 100

This sends 100 requests and provides a more useful packet-loss and latency sample.

To run Ping continuously:

ping btc-eu.pecpool.com -t

Press Ctrl + C to stop the continuous test and display the final statistics.

Run a Ping Test in Linux

Open a terminal and enter:

ping -c 20 btc-eu.pecpool.com

This sends 20 requests and then displays the result.

For a longer test:

ping -c 100 btc-eu.pecpool.com

To run Ping continuously:

ping btc-eu.pecpool.com

Press Ctrl + C to stop the test.

How to Read Ping Results

Important Ping values include:

Value	Meaning
Sent	Number of test packets transmitted
Received	Number of replies received
Lost	Number of packets that did not return
Minimum	Lowest measured response time
Maximum	Highest measured response time
Average	Average round-trip response time

Understanding Latency

Latency is the time required for a packet to travel to the server and for the reply to return. It is normally measured in milliseconds.

Lower latency is generally useful because mining jobs and submitted shares can travel more quickly.

However, the server with the lowest Ping is not always the best server.

Compare these examples:

Server A

Average Ping: 42 ms
Packet Loss: 4%
Frequent Timeouts: Yes

Server B

Average Ping: 86 ms
Packet Loss: 0%
Frequent Timeouts: No

Server B may provide better mining performance because its connection is more stable even though its average latency is higher.

What Is Packet Loss?

Packet loss occurs when data sent across the network does not reach its destination or the reply does not return.

Packet loss may cause:

• Delayed mining jobs
• Stale shares
• Stratum reconnections
• Pool Dead errors
• Hashrate chart gaps
• Workers becoming Offline

The ideal packet-loss result is:

0%

Occasional loss may occur on some internet paths, but persistent packet loss should be investigated.

Signs of an Unstable Ping Result

An unstable result may show:

• Repeated Request Timed Out messages
• Significant packet loss
• Latency changing from 40 ms to several hundred milliseconds
• Long periods without replies
• Problems occurring at the same time each day

Large and repeated latency spikes can indicate network congestion, wireless instability, router overload, or ISP routing problems.

Ping Failure Does Not Always Mean Mining Failure

Some servers, firewalls, and network providers block or limit ICMP Ping traffic.

If Ping fails but:

• The miner displays the pool as Alive or Connected,
• Accepted shares are increasing, and
• The worker is Online in PECPool,

the failed Ping result alone does not indicate a mining problem.

Use a TCP port test to check the actual stratum connection.

What Is DNS?

DNS converts a hostname such as:

btc-eu.pecpool.com

into an IP address that network devices can use.

If DNS fails, the miner cannot determine where the PECPool server is located, even when its general internet connection is working.

Common Signs of a DNS Problem

• DNS Lookup Failed in the miner log
• Host Not Found
• Unknown Host
• The miner can reach IP addresses but not domain names
• All pool hostnames remain Dead
• Restarting the router temporarily solves the problem

Test DNS in Windows Command Prompt

Use:

nslookup btc-eu.pecpool.com

A successful result should normally display one or more IP addresses.

Example:

Name: btc-eu.pecpool.com
Address: 203.0.113.10

The displayed IP address above is only an example. Always use the actual result returned by DNS.

Test DNS in Windows PowerShell

Use:

Resolve-DnsName btc-eu.pecpool.com

The command may show:

• The hostname
• Record type
• Time to live
• Resolved IP address

Test DNS in Linux

Use one of the following commands:

getent hosts btc-eu.pecpool.com

or:

nslookup btc-eu.pecpool.com

If available, you can also use:

dig btc-eu.pecpool.com

Compare Different DNS Resolvers

A domain may fail through one DNS resolver but work through another.

Windows example:

nslookup btc-eu.pecpool.com 1.1.1.1

Another example:

nslookup btc-eu.pecpool.com 8.8.8.8

Use DNS resolvers permitted by your network administrator and local network policy.

If the hostname resolves through one resolver but not the router's default resolver, investigate the router or ISP DNS service.

Do Not Permanently Replace the Hostname with an IP Address

DNS testing may show the current IP address of a PECPool server.

Do not permanently configure that IP address in the ASIC miner unless PECPool Support specifically instructs you to do so.

Server IP addresses may change because of:

• Infrastructure maintenance
• Load balancing
• Routing improvements
• Server migrations
• Failover changes

The official hostname allows the miner to resolve the appropriate destination automatically.

Clear the Windows DNS Cache

If Windows is using an outdated or incorrect DNS result, open Command Prompt as Administrator and use:

ipconfig /flushdns

Then test the hostname again:

nslookup btc-eu.pecpool.com

This command affects the Windows computer. It does not directly clear the DNS cache inside the ASIC miner or router.

Check the Miner's DNS Settings

If a computer resolves PECPool correctly but the miner reports a DNS error, check the miner's network configuration.

Verify:

• The miner has a valid IP address.
• The subnet mask is correct.
• The default gateway is reachable.
• A valid DNS server is configured.
• There is no duplicate IP address.

What Is a TCP Port Test?

A TCP port test checks whether a specific server port can be reached from the tested network.

This is more relevant to mining than Ping because ASIC miners connect to PECPool through specific stratum TCP ports.

A successful DNS result does not guarantee that the stratum port is open.

Test a PECPool Port in Windows PowerShell

Test the Europe server on port 3333:

Test-NetConnection btc-eu.pecpool.com -Port 3333

Test port 443:

Test-NetConnection btc-eu.pecpool.com -Port 443

Test port 25:

Test-NetConnection btc-eu.pecpool.com -Port 25

Look for:

TcpTestSucceeded : True

A result of True means the tested computer successfully established a TCP connection to that hostname and port.

Test a PECPool Port in Linux

Using Netcat:

nc -vz btc-eu.pecpool.com 3333

Test port 443:

nc -vz btc-eu.pecpool.com 443

Test port 25:

nc -vz btc-eu.pecpool.com 25

If Netcat is not installed, use the appropriate package-management method for your Linux distribution or another approved TCP diagnostic tool.

What a Successful Port Test Confirms

A successful TCP test confirms that:

• The hostname resolved successfully.
• A network route to the destination exists.
• The tested TCP port accepted a connection.

It does not confirm that:

• The mining account name is correct.
• The worker name is correct.
• The miner uses the SHA-256 algorithm.
• Shares will be accepted.
• The connection will remain stable for several hours.

These items must be verified through the miner status page and PECPool panel.

What a Failed TCP Port Test May Mean

• The selected port is blocked by the router.
• The ISP filters the port.
• The hostname or port is incorrect.
• The firewall blocks outbound connections.
• The tested network has a routing problem.
• The destination is temporarily unreachable from that route.

If one port fails, test another supported port on the same PECPool hostname.

Port 443 Does Not Automatically Mean Encryption

PECPool provides port 443 as an alternative stratum connection port.

For example:

stratum+tcp://btc-eu.pecpool.com:443

This address still uses the stratum+tcp:// protocol. The port number alone does not make the connection HTTPS or encrypted.

Port 25 May Be Restricted

Port 25 is commonly associated with email traffic and may be restricted by some internet providers, hosting companies, or firewalls.

Do not assume that port 25 will work on every network. Test it using a TCP port test.

Test the Network Route in Windows

Use:

tracert btc-eu.pecpool.com

This displays the network hops between your computer and the destination.

It can help identify:

• Where latency begins increasing
• Where the route stops responding
• Whether traffic is following an unexpected path
• Whether international routing is involved

Test the Network Route in Linux

Use:

traceroute btc-eu.pecpool.com

If traceroute is not installed, install it using the approved method for your Linux distribution.

Some routers do not reply to traceroute probes. An asterisk at one hop does not always mean that traffic cannot continue beyond that point.

Use PathPing in Windows

PathPing combines parts of Ping and route testing. It measures packet loss across network hops over a longer period.

Use:

pathping btc-eu.pecpool.com

The test may take several minutes to complete.

PathPing can help identify whether packet loss appears:

• Inside the local network
• At the ISP gateway
• Further along the internet route

Some network devices intentionally limit diagnostic replies, so interpret individual-hop loss carefully. The final destination result and actual mining behavior are more important.

Use MTR in Linux

MTR combines continuous Ping and route analysis.

Example:

mtr -rwzc 100 btc-eu.pecpool.com

This can display:

• Network hops
• Packet loss
• Average latency
• Best and worst response times
• Latency variation

MTR is especially useful for identifying intermittent routing or packet-loss problems.

Understanding Route-Test Timeouts

A timeout or asterisk at an intermediate hop does not always indicate packet loss affecting normal traffic.

Some routers:

• Do not answer diagnostic requests
• Give low priority to Ping or traceroute traffic
• Limit the number of diagnostic replies

If later hops and the final destination respond normally, the intermediate timeout may not represent a real connection problem.

How to Test Long-Term Network Stability

A four-packet Ping test may look normal even when the connection fails periodically.

For better testing:

• Run at least 100 Ping requests.
• Run continuous Ping during the normal problem period.
• Record the time of each pool disconnection.
• Compare miner logs with Ping timeouts.
• Repeat the test during peak internet hours.

Windows Continuous Test

ping btc-eu.pecpool.com -t

Linux Long Test

ping -c 1000 btc-eu.pecpool.com

Stop the test after a sufficient period and review packet loss and latency variation.

Save Ping Results to a File in Windows

Use:

ping btc-eu.pecpool.com -t > pecpool-ping.txt

Press Ctrl + C to stop the test.

The results will be saved in the current directory as:

pecpool-ping.txt

This file can help compare network interruptions with miner logs.

Save Ping Results to a File in Linux

Use:

ping btc-eu.pecpool.com | tee pecpool-ping.txt

Press Ctrl + C to stop the test.

Test the Local Gateway

Before blaming the internet route, test the local router or gateway.

Example:

ping 192.168.1.1

Replace the example address with the actual gateway used by the mining network.

Packet loss to the local gateway may indicate:

• A damaged Ethernet cable
• A failing switch port
• Wireless instability
• A router problem
• Local network congestion
• A duplicate IP address

Compare Local and Internet Tests

Gateway Test	PECPool Test	Likely Area
Unstable	Unstable	Local network, cable, switch, or router
Stable	Unstable	ISP, internet route, filtering, or remote path
Stable	Stable	Check miner configuration, firmware, or hardware
Ping fails	Mining works	ICMP may be blocked; verify TCP and accepted shares

Check for Duplicate IP Addresses

Duplicate local IP addresses can create intermittent network failures.

Possible signs include:

• The miner management page opens and closes unexpectedly.
• Ping replies come from different devices.
• The miner repeatedly disconnects from the pool.
• The router client list changes unexpectedly.

Review the router's DHCP client list and make sure every miner has a unique IP address.

Check Ethernet Cables and Switch Ports

Physical network problems are a common cause of instability.

Check:

• The Ethernet cable is fully inserted.
• The cable is not damaged or sharply bent.
• The miner network-port LEDs are active.
• The switch port shows a stable link.
• A different cable has been tested.
• A different switch port has been tested.

If only one miner has connectivity problems, test its cable and switch port before changing the entire network configuration.

Avoid Unstable Wireless Connections

ASIC miners are normally designed for wired Ethernet connections.

Wi-Fi adapters, wireless bridges, and long-distance wireless links may introduce:

• Packet loss
• Latency spikes
• Interference
• Brief disconnections
• Higher stale-share rates

Use wired Ethernet whenever possible.

Check Router and Firewall Rules

A firewall may allow normal web browsing while blocking mining ports.

Check:

• Outbound TCP rules
• Port restrictions
• DNS filtering
• VLAN rules
• Connection limits
• ISP filtering
• Security software policies

The miner must be able to create an outbound TCP connection to the selected PECPool hostname and port.

Check Router Capacity

A router handling many miners and connections may become overloaded.

Possible signs include:

• Many workers disconnecting at the same time
• Increasing latency during busy periods
• Router CPU or memory usage becoming high
• Connection tables reaching capacity
• Router restarts temporarily solving the problem

Review router resources, logs, firmware, and connection limits.

Check Mining Proxy Stability

When miners connect through a mining proxy, test both parts of the route:

1. Miner to proxy
2. Proxy to PECPool

Check:

• Proxy CPU usage
• Proxy memory usage
• Connected miner count
• Network interface capacity
• Proxy logs
• Latency to PECPool

When practical, temporarily connect one affected miner directly to PECPool. If the direct connection is stable, investigate the proxy or its local network path.

Compare PECPool Regional Servers

Test more than one official PECPool server from the mining network.

For example:

ping btc-eu.pecpool.com
ping btc.pecpool.com
ping btc-us.pecpool.com

Then test the required ports:

Test-NetConnection btc-eu.pecpool.com -Port 3333
Test-NetConnection btc.pecpool.com -Port 443
Test-NetConnection btc-us.pecpool.com -Port 25

Select the server that provides the most stable actual mining connection, not only the lowest single Ping result.

Recommended Pool Configuration

Configure three official PECPool addresses for failover.

Example for Europe

Pool 1: stratum+tcp://btc-eu.pecpool.com:3333
Pool 2: stratum+tcp://btc.pecpool.com:443
Pool 3: stratum+tcp://btc-us.pecpool.com:25

Example for Iran

Pool 1: stratum+tcp://btc.pecpool.cc:8443
Pool 2: stratum+tcp://btc-as.pecpool.com:443
Pool 3: stratum+tcp://btc-eu.pecpool.com:3333

Using different hostnames and ports provides greater routing diversity.

How to Confirm a Network Change Improved Mining

After changing a server, port, cable, switch, DNS setting, or router configuration:

1. Save the miner configuration.
2. Confirm that the pool shows Alive or Connected.
3. Confirm that accepted shares begin increasing.
4. Review rejected and stale shares.
5. Check the worker's last-share time.
6. Review the 1-hour and 24-hour PECPool hashrate.
7. Monitor the connection for several hours.

Do not decide that a change succeeded based only on one successful Ping.

Example 1: DNS Failure

The miner log displays:

DNS Lookup Failed

The computer test shows:

nslookup btc-eu.pecpool.com
Server failed

Recommended checks:

• Review the router DNS configuration.
• Confirm the miner gateway.
• Test another approved DNS resolver.
• Restart the router or DNS service if required.
• Retest the hostname.

Example 2: Port 3333 Is Blocked

DNS works:

Resolve-DnsName btc-eu.pecpool.com
Result: Successful

Port test fails:

Test-NetConnection btc-eu.pecpool.com -Port 3333
TcpTestSucceeded: False

Port 443 works:

Test-NetConnection btc-eu.pecpool.com -Port 443
TcpTestSucceeded: True

Configure the supported working port and confirm that accepted shares begin increasing.

Example 3: Local Network Packet Loss

Gateway test:

Packets: Sent = 100, Received = 90, Lost = 10
Loss: 10%

Because packet loss already exists between the computer and local gateway, investigate:

• Ethernet cable
• Switch port
• Wireless bridge
• Router
• Duplicate IP address

Example 4: Stable Local Network but Unstable Internet Route

Gateway result:

Packet Loss: 0%
Average: 1 ms

PECPool route result:

Packet Loss: 4%
Latency: 60 ms to 450 ms
Frequent Timeouts: Yes

The local network appears stable. Investigate ISP routing, internet congestion, the selected PECPool region, or another supported port.

Example 5: Ping Fails but Mining Works

Ping result:

Request Timed Out

Miner status:

Pool Status: Alive
Accepted Shares: Increasing
Worker Status: Online

The destination may be blocking ICMP Ping. No mining change is required based only on the failed Ping.

Recommended Testing Order

1. Confirm the miner's Pool URL and port.
2. Test the local gateway.
3. Test DNS resolution.
4. Test the exact stratum TCP port.
5. Run a longer Ping test.
6. Check packet loss and latency variation.
7. Run traceroute, PathPing, or MTR.
8. Test another PECPool port.
9. Test another PECPool regional hostname.
10. Inspect cables, switches, router, and firewall.
11. Compare the results with miner logs.
12. Confirm accepted shares and PECPool worker status.

Do Not Change Multiple Settings at Once

Changing DNS, router rules, Pool URL, port, Ethernet cable, and miner firmware simultaneously makes it difficult to identify the real cause.

Use a controlled process:

1. Record the current results.
2. Change one item.
3. Repeat the same test.
4. Monitor the miner.
5. Keep or reverse the change.

Common Testing Mistakes

• Testing from a different internet provider than the miners
• Using only four Ping requests
• Assuming failed Ping means the stratum port is down
• Testing the website instead of the stratum hostname
• Testing port 3333 when the miner uses port 443
• Ignoring packet loss
• Selecting a server only from the lowest Ping result
• Replacing the hostname permanently with an IP address
• Ignoring miner logs and accepted shares
• Changing several settings simultaneously

Quick Command Reference

Purpose	Windows	Linux
Basic Ping	ping btc-eu.pecpool.com	ping -c 20 btc-eu.pecpool.com
Long Ping Test	ping btc-eu.pecpool.com -n 100	ping -c 100 btc-eu.pecpool.com
DNS Test	nslookup btc-eu.pecpool.com	getent hosts btc-eu.pecpool.com
TCP Port Test	Test-NetConnection btc-eu.pecpool.com -Port 3333	nc -vz btc-eu.pecpool.com 3333
Route Test	tracert btc-eu.pecpool.com	traceroute btc-eu.pecpool.com
Extended Route Test	pathping btc-eu.pecpool.com	mtr -rwzc 100 btc-eu.pecpool.com

Final Checklist

• Tests were performed from the same network used by the ASIC miners.
• The exact PECPool hostname configured in the miner was tested.
• The exact stratum port was tested.
• DNS returns a valid result.
• The TCP port test succeeds.
• The local gateway has no packet loss.
• The internet route has no persistent packet loss.
• Latency does not show repeated extreme spikes.
• Ethernet cables and switch ports are stable.
• The router and firewall allow outbound stratum connections.
• Pool 1, Pool 2, and Pool 3 are configured.
• Accepted shares are increasing.
• The worker appears Online in PECPool.
• Rejected and stale shares remain low and stable.

Use Mining Results as the Final Test

Ping, DNS, TCP port tests, traceroute, PathPing, and MTR are useful diagnostic tools, but the final test is the miner's actual connection to PECPool.

A stable mining connection should show:

• The active pool as Alive or Connected
• Accepted shares increasing
• A recent last-share time
• The worker remaining Online
• Low rejected and stale share rates
• A stable 1-hour and 24-hour hashrate

Use network tests to identify the source of a problem, then confirm the result through actual PECPool mining activity.