http://en.wikipedia.org/wiki/Remote_shell

root@gate:~# apt-get install rsh-server

[gate:~] # cat /etc/inetd.conf

...
shell  stream  tcp     nowait  root    /usr/libexec/rshd       rshd
login  stream  tcp     nowait  root    /usr/libexec/rlogind    rlogind
...

student@client1:~# apt-get install rsh-client

gate# su - user1

$ cat .rhosts

client1 root
client1

client1$ rsh gate "uname -a"

client1$ cat /etc/hosts | rsh gate "cat > hosts.bak"

client1$ rcp /etc/hosts gate:hosts.bak

client1$ rlogin gate

client1# rsh -l user1 gate "uname -a"

client1# rcp /etc/shadow user1@gate:
client1# rcp /etc/master.passwd user1@gate:

client1# cd /
client1# tar -cvf - etc/ | rsh -l user1 gate "cat > etc.tar"

http://ru.wikipedia.org/wiki/Telnet

root@gate:~# apt-get install telnetd

root@gate:~# cat /etc/inetd.conf

[gate:~] # cat /etc/inetd.conf

...
telnet stream  tcp     nowait  root    /usr/libexec/telnetd    telnetd
...