Another word of caution. If someone can gain root access on a machine you log into with the -A flag they can "borrow" your authentication agent and use your ke

Another word of caution. If someone can gain root access on a machine you log into with the -A flag they can "borrow" your authentication agent and use your keys. It's only borrowing because the connection to the agent disappears once you log off. But by then they could already have added new keys for themselves on your other severs.