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Code42 Support

Test your network connection with Telnet

Applies to:
  • CrashPlan PRO
  • CrashPlan PROe

Overview

For most backup destinations, the CrashPlan app must have network access using specific ports. If your CrashPlan app cannot back up to the Code42 cloud or to another computer, you can test your CrashPlan app's network access using a tool called Telnet.

This article describes how to use Telnet to diagnose whether your CrashPlan app is affected by network issues, including conflicts from firewalls or antivirus software. You can use Telnet to test two types of connections:

Before you begin

On a Windows computer, you must turn on Telnet before you can use it.

  1. Click Start.
  2. Click Control Panel.
  3. Click Programs and Features.
  4. Click Turn Windows features on or off.
  5. Select the Telnet Client so that the checkbox is filled.
  6. Click OK.

On Linux or OS X, you can use Telnet by default.

Test your connection to the Code42 cloud

Step 1: Run telnet

  1. Open a command prompt on your computer.
      • Windows:
        • Windows 10 and Windows 8: Start > All Apps > Windows System > Command Prompt
        • Windows 7: Start > All Programs > Accessories > Command Prompt
      • OS X: Applications > Utilities > Terminal
      • Linux: Open Terminal or another command prompt for your distribution.
  2. Enter the telnet command for your CrashPlan product:
    • CrashPlan for Home: telnet central.crashplan.com 443
    • CrashPlan PRO: telnet central.crashplanpro.com 443
    • Code42 for Enterprise: telnet central.crashplan.com 443

Step 2: Read the telnet response

If your command prompt shows the following Connected message, your CrashPlan app can successfully connect to the Code42 cloud:

telnet central.crashplan.com 443
Trying 192.0.2.1...
Connected to central.crashplan.com.
Escape character is '^]'.
?cA-18782|com.code42.messaging.security.SecurityProviderReadyMessage??"???Q??????OM???`q?????N??6C:

If your command prompt shows anything else, your CrashPlan app cannot connect to the Code42 cloud. Common failure messages include:

  • Connection refused
  • Operation timed out
  • Unable to connect to remote host
  • No response

Step 3: Troubleshoot a failed connection

If your Telnet test did not connect to the Code42 cloud, your issue is caused by your computer or network, not by the CrashPlan app. Check the following common causes of this issue:

  • Your router's network configuration or port forwarding settings
  • Other conflicting software on your computer, such as antivirus, security, or parental control software

Test your connection to another computer

Step 1: Identify the computer's network information

To test your connection to another computer, you must use the other computer to identify its IP address and port.

Identify the IP address

Identify the other computer's IP address from its CrashPlan app:

  1. Open the CrashPlan app.
  2. Go to Backup.
  3. Click your computer's name.
  4. Record the IP address that's being used.
    • If both computers are in the same local network (such as in the same house, generally): use the Internal IP address.
    • If the computers communicate over the Internet (such as being in two different houses): use the Public IP address.

Identify the port

Identify the port used by the other computer's CrashPlan app:

  1. Open the CrashPlan app.
  2. Double-click the CrashPlan logo in the upper-right corner.
    The command-line interface appears.
  3. Enter the following command: connection.info
  4. Press Enter.

The port is the number on the line that starts with Port. For example, this example shows a CrashPlan app using port 4242:

connection.info
Address=127.0.0.1
Port=4242
UI Port=4243
HTTP Port=4244

Step 2: Run telnet

  1. Open a command prompt.
      • Windows:
        • Windows 10 and Windows 8: Start > All Apps > Windows System > Command Prompt
        • Windows 7: Start > All Programs > Accessories > Command Prompt
      • OS X: Applications > Utilities > Terminal
      • Linux: Open Terminal or another command prompt for your distribution.
  2. Enter the telnet command with the other computer's network information.
    • Use this format:
      telnet <IP address> <port>
    • For example:
      telnet 192.0.2.100 4242

Step 3: Read the telnet response

If your command prompt shows the following Connected message, your CrashPlan app can successfully connect to the other computer:

telnet 192.0.2.100 443
Trying 192.0.2.100...
Connected to 192.0.2.100.
Escape character is '^]'.
?cA-18782|com.code42.messaging.security.SecurityProviderReadyMessage??"???Q??????OM???`q?????N??6C:

If your command prompt shows anything else, your CrashPlan app cannot connect to the other computer. Common failure messages include:

  • Connection refused
  • Operation timed out
  • Unable to connect to remote host
  • No response

Step 4: Troubleshoot a failed connection

If your Telnet test did not connect to the other computer, your issue is caused by the computers or network configuration, not by the CrashPlan app. Check the following common causes of this issue:

  • Either computer's router, including its network configuration or port forwarding settings
  • Other conflicting software on either computer, such as antivirus, security, or parental control software

External references

These resources provide more information on the computer networking concepts in this article: