Mobile Ad-hoc Network (MANET) can be implemented anywhere where there is little or no communication infrastructure, or the existing infrastructure is inconvenient to use. A number of people with mobile devices may connect together to form one large group. Later on, they may split into smaller separate groups and partitions may merge if necessary. Network partitions and merges are potentially frequent occurrences in MANETs, hence address auto-configuration is an important requirement. In this paper we present a mechanism for address auto-configuration in MANETs, which is capable of assigning conflict-free addresses in a dynamic and distributed manner. Also we propose novel mechanisms to address MANET partition and merging.