# Revision history [back]

### TurtleBot unable to contact my own server

A question from Mac Howard:

I am having a problem getting the turtlebot minimal.launch program to run. It gives me the following error:

Unable to contact my own server at [http://IP_OF_LAPTOP:42375/].
This usually means that the network is not configured properly.


A common cause is that the machine cannot ping itself. Please check for errors by running:

ping ip_of_laptop


http://www.ros.org/wiki/ROS/NetworkSetup

I have checked both .bashrc files and they have the following lines in them:

Laptop .bashrc file:

export ROS_MASTER_URI=http://IP_OF_LAPTOP:11311
export ROS_HOSTNAME=IP_OF_LAPTOP


Workstation .bashrc file:

export ROS_MASTER_URI=http://IP_OF_LAPTOP:11311
export ROS_HOSTNAME=IP_OF_WORKSTATION


I have tried replacing those with the actual IP addresses and that did not work either, and documentation I found on the net advised that the way I have it above was correct. I also don't understand on a fundamental level where it assigns "IP_OF_LAPTOP" or"IP_OF_WORKSTATION" to the actual number.

I went through the NetworkSetup tutorial and the EnvirmonmentVariables turtorial with no luck. My computers also do not have names on the network (aka they cannot be accessed with a URL other than their ip address. Do you have any suggestions? Thank you very much!

 2 typo tfoote 52751 ●99 ●359 ●452 http://www.ros.org/

### TurtleBot unable to contact my own server

A question from Mac Marc Howard:

I am having a problem getting the turtlebot minimal.launch program to run. It gives me the following error:

Unable to contact my own server at [http://IP_OF_LAPTOP:42375/].
This usually means that the network is not configured properly.


A common cause is that the machine cannot ping itself. Please check for errors by running:

ping ip_of_laptop


http://www.ros.org/wiki/ROS/NetworkSetup

I have checked both .bashrc files and they have the following lines in them:

Laptop .bashrc file:

export ROS_MASTER_URI=http://IP_OF_LAPTOP:11311
export ROS_HOSTNAME=IP_OF_LAPTOP


Workstation .bashrc file:

export ROS_MASTER_URI=http://IP_OF_LAPTOP:11311
export ROS_HOSTNAME=IP_OF_WORKSTATION


I have tried replacing those with the actual IP addresses and that did not work either, and documentation I found on the net advised that the way I have it above was correct. I also don't understand on a fundamental level where it assigns "IP_OF_LAPTOP" or"IP_OF_WORKSTATION" to the actual number.

I went through the NetworkSetup tutorial and the EnvirmonmentVariables turtorial with no luck. My computers also do not have names on the network (aka they cannot be accessed with a URL other than their ip address. Do you have any suggestions? Thank you very much!