DOCS-2998 covers a segment of this, however this change need to made explicit in our Linux .deb and .rpm package. The default settings of the configuration file prevent replicasets from functioning without editing and many customers will hit this unless clearly highlighted.
Specifically in the sections:
E.g.
Please note in the 2.6 series in the mongod.conf file, the bind_ip configuration set to 127.0.0.1 by default.