Hello! We have production setup of three nodes in replica sets, elba-mongo1 on one rack (the primary) and elba-mongo2, elba-mongo3 on another (secondaries).
Periodically in our mongo logs we see something similar to:

Wed Jan 16 11:59:13 [rsBackgroundSync] replSet syncing to: elba-mongo1:27017
Wed Jan 16 11:59:16 [rsHealthPoll] DBClientCursor::init call() failed
Wed Jan 16 11:59:16 [rsHealthPoll] replSet info elba-mongo1:27017 is down (or slow to respond): DBClientBase::findN: transport error: elba-mongo1:27017 ns: admin.$cmd query: { replSetHeartbeat: "rs0", v: 6, pv: 1, checkEmpty: false, from: "elba-mongo3:27017", $auth: {} }

After this point there is an election of new primary. elba-mongo1 pinged successfully from both elba-mongo2 and 3, but we can't connect to elba-mongo1 instance from elba-moongo1 machine using mongo console - it just hangs on "connecting to":

Croot@elba-mongo1:~# telnet localhost 27017
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
^]
telnet> quit
Connection closed.
root@elba-mongo1:~# mongo
MongoDB shell version: 2.2.2
connecting to: test