Telnet and rlogin do not usually come with any effective protection other than simple password schemes. Data and even the password is transmitted as plain text. There are commonly available programs that constantly monitor the network for packets that contains passwords. Fortunately, the security of these protocols can be vastly improved by replacing them with the Secure Shell protocoll (http://www.cs.hut.fi/ssh). Preferably, all telnet and rlogin servers and clients should be removed from all machines.