MongoDB supports a DNS-constructed seed list. Using DNS to construct the available servers list allows more flexibility of deployment and the ability to change the servers in rotation without reconfiguring clients.
In order to leverage the DNS seedlist, use a connection string prefix of mongodb+srv: rather than the standard mongodb:. The +srv indicates to the client that the hostname that follows corresponds to a DNS SRV record. The driver or mongo shell will then query the DNS for the record to determine which hosts are running the mongod instances