First, we will deal with peer-to-peer networks where two Moodle servers are connected. For demonstration purposes, we have set up two Moodle sites (two peers), one is located at http://packt1.synergy-learning.com and the other at http://packt2.synergy-learning.com. The two sites do not have to be in the same domain or the same organization. For example, two universities or two high schools might want to offer a collaborative course. They both have their own Moodle system in their own domain and they both control who gets access to which part of their site.
If your two sites are hosted in the same domain and you are accessing both sites from the same web browser simultaneously, change the cookie prefix of one site (Server | Session handling) to avoid any conflicts.