无法连接127.0.0.1:6633远程控制器，Mininet新手求助

Hey there! Let's break down why you're getting that error message when running your Mininet script. Here are the most common issues and how to fix them:

1. Your Remote Controller Isn't Running Locally #

The biggest culprit here is that the controller you're trying to connect to (like POX, OpenDaylight, or ONOS) isn't actually running on your local machine (127.0.0.1) on port 6633.

• First, start your controller:
  • For POX: Run ./pox.py forwarding.l2_learning from the POX directory.
  • For OpenDaylight: Follow its official startup instructions to launch the controller service.
• Verify the controller is listening on port 6633 with this command:

  sudo netstat -tulpn | grep 6633
  

  You should see an entry showing the controller process actively using that port.

2. The Controller Uses a Different Default Port #

Some controllers don't use 6633 by default. For example:

• ONOS defaults to port 6653
• Older OpenDaylight versions might use 6640

Check your controller's documentation for its default OpenFlow port, then update your script's port parameter in the addController line:

net.addController( 'c0', controller=RemoteController, ip='127.0.0.1', port=YOUR_CONTROLLER_PORT )

3. Firewall is Blocking the Connection #

Your local firewall might be preventing Mininet from reaching the controller on port 6633.

• Temporarily disable the firewall to test:

  sudo ufw disable
  

• If that fixes it, add a permanent rule to allow traffic on port 6633:

  sudo ufw allow 6633/tcp
  

4. Switch Controller Configuration #

Sometimes Mininet doesn't properly attach switches to the remote controller. After starting the Mininet CLI, check each switch's controller status:

mininet> sh ovs-vsctl show

Look for entries like Controller "tcp:127.0.0.1:6633" under each switch. If missing, manually attach the controller to each switch:

mininet> sh ovs-vsctl set-controller s1 tcp:127.0.0.1:6633
mininet> sh ovs-vsctl set-controller s2 tcp:127.0.0.1:6633
mininet> sh ovs-vsctl set-controller s3 tcp:127.0.0.1:6633

Once you've addressed the issue, restart your Mininet script and the error should disappear.

内容的提问来源于stack exchange，提问作者Mohammed