FTP AND TFTP—
These are the servers for used for file transfer.
FTP-file transfer protocol
:uses TCP
:FTP uses port 20 (for data) and 21 (for control)
:in this connections are made and then file transfer is done
:in this acknowledgement is provided
:for example – email
:for FTP we have package VSFTPD(very secure file transfer protocol demon)
TFTP-Trivial file transfer protocol
:Uses UDP
:it uses port 69
:no connection is made
:no acknowledgement is needed
:only need port no. and ip address
:for fast transfer.
:example- sms
:for TFTP we have package called XINETD.
SSH AND TELNET—–
These servers are used for remote login.
SSH-Secure shell
:it is more secured as it is in encrypted form
:it can be used only in network
:if outside the network then port forwarding is done
:it uses TCP port 22
:using this we cannot transfer the file but
:we can copy it by using—–
scp source destination —-scp 192.168.1.12/filename home/emblogic
:we use SSHD server for this
:we have a intresting thing in this i.e WALL
:try out afer installing ssh
:write ssh 127.0.0.1(an ip address of your friend)
:then write wall “hello”
:hello will be shown on your friends desktop….
TELNET
:This server has more authentication
:i.e ask for password and username
:uses TCP
:the WALL function does not work in this
:uses port no.23
