remote access, when needed, should only be thru SSH and never thru telnet. Disabling telnet is the first thing that you must do before you connect your machine to the network. SSH, by default, may be secure but there are more ways to make it more secure. Anze Vidmar writes for Linux.com and gives us more tips on how to lock-down SSH and provide a more secure remote access.
Remember that you must only enable remote access when necessary. Shut it down if you don't need it.