You should be able to run this command and get a list of connected IP addresses:
db.currentOp(true).inprog.forEach(function(d){if (d.client)printjson(d.client)})
db.currentOp $cmd.sys.inprog, . , , db.currentOp mongo, :
> db.currentOp
function ( arg ){
var q = {}
if ( arg ) {
if ( typeof( arg ) == "object" )
Object.extend( q , arg );
else if ( arg )
q["$all"] = true;
}
return this.$cmd.sys.inprog.findOne( q );
}