# Revision history [back]

Really, setting $ROS_IP and$ROS_HOSTNAME should be mutually exclusive. If you need to specify your machine explicitly, choose one or the other.

Then you have two options:

1. set $ROS_MASTER_URI to either "http://flyatar:11311" or "http://172.25.253.72:11311" depending on whether you're using $ROS_HOSTNAME or $ROS_IP, respectively. 2. Un-set $ROS_IP and un-set $ROS_HOSTNAME, leaving $ROS_MASTER_URI as "http://localhost:11311".

Really, setting $ROS_IP and$ROS_HOSTNAME should be mutually exclusive. If you need to specify your machine explicitly, choose one or the other.

Then you have two options:

1. set Set $ROS_MASTER_URI to either "http://flyatar:11311" or "http://172.25.253.72:11311" depending on whether you're using $ROS_HOSTNAME or $ROS_IP, respectively. 2. Un-set $ROS_IP and un-set $ROS_HOSTNAME, leaving $ROS_MASTER_URI as "http://localhost:11311".