Connecting aws mongo database from localhost?

I am trying to connect to the aws mongodb database from the localhost by configuring robomongo but it is responding as unable to connect each time. when i am checking that mongodb is running on aws

service mongod status

then is it showing

mongod start/running, process 20934

Is this correct way of checking whether mongodb is running or not ? i am adding two ports in security inbound for mongodb 27017 and 28017

for mongodb and in Robomongo i am providing name aws

address -amazon ec2 address of instance

port 27017

can anybody tell what is wrong in this process?