Linux Server
Linux,like UNIX,is an excellent operating system for Internet servers,including
Web,e-mail,and FTP servers.The vast networking capability of the Linux oper-
ating system makes it a prime candidate to be used as a server in any kind of net-
working environment.Linux supports all of the most common Internet protocols.
Following is a list of some of the protocols supported by Linux: FTP SMNP HTTP POP SMTP Telnet SSH NNTP
Linux has already been widely used and tested on all of these listed protocols.Let
me now discuss each of these protocols.
FTP
File Transfer Protocol(FTP) is one of oldest Internet protocols,and it is still being
used extensively. FTP is a part of the Internet protocol suite that can be used to
transfer files between two computers. FTP works in two modes: text and binary
transfer mode.Many FTP servers such as WS-FTP are available for Linux.Using
FTP,you can access files stored in the disk directory of a remote computer.FTP
is used to do the following: Share files,which might include computer programs and data Indirectly or implicitly use remote computers Shield a user from variations in file storage systems among hosts Transfer data reliably and efficiently
SNMP
Simple Network Management Protocol (SNMP) is a network management proto-
col. It was developed in 1988 to provide a framework for network management.
Some typical purposes for which SNMP can be used are these: Assigning addresses to devices Prioritizing communication Installing software on a network Managing printer queues
Over the years, SNMP has become the standard protocol for internetwork man-
agement.In the manager/agent model,which is adopted by the SNMP protocol,
the processing capability resides on the management system. The management
system is responsible for issuing messages such as
Get,GetNext,and Set.You use
these messages to obtain or store the value of variables.These messages are sent
to the agent responsible for sending a response back to the management system.
HTTP Protocol
HyperText Transfer Protocol(HTTP) is the standard protocol used for transferring
documents on the World Wide Web. HTTP is employed in the client/server
architecture. After a successful connection is established between server and
client,the client can send requests for resources,such as Web pages,on the server.
The server then sends the requested resource back to the client. HTTP operates
over TCP connections, usually at port 80, though this can be overridden and
another port can be used.
POP Protocol
Post Office Protocol(POP) is a messaging protocol that enables users to access their
mailboxes.The POP protocol is based on a client/server model.The messages are
stored in the server.Users download these messages to their computer by using a
POP client, such as Eudora. POP provides for user authentication by authenti-
cating users through passwords.However,passwords are transmitted as clear text,
which means that POP should be used very carefully because the password trans-
mission method is not secure.
SMTP Protocol
Simple Mail Transfer Protocol (SMTP) is a messaging protocol responsible for
delivering mail.It relays mail messages from an SMTP client to the SMTP server
and from one SMTP server to another.In case of delivery failure of mail,the mes-
sages are queued up in the SMTP server.The SMTP server again tries to deliver
these queued messages.Two popular SMTP servers for Linux are Sendmail and
qmail.
Telnet Protocol
The Telnet protocol enables you to remotely log on to a computer on a network.
The Telnet protocol is based on the client/server model.The computer that tries
to connect to the server from a remote location is the client. On the other hand,
the computer to which the request is being made and that allows establishment of
the connection is the server.The connection between the two computers is estab-
lished based on some pre-defined criteria, such as the terminal type to be used.
The username you specify during the connection determines your access on the
destination’s computers files and directories.
SSH Protocol
The Secure Shell (SSH) is a protocol for encrypting TCP sessions over the Inter-
net. The primary use of SSH is remote login. However, it also can be used as a
cryptographic tunnel.This tunnel generated by the SSH can be used for various
purposes,such as copying files,encrypting e-mail connections,and triggering the
remote execution of programs.
Before establishing connection between two computers, SSH connects to the
server, performs secret key negotiation between the two computers, and starts
encrypting the session after successful negotiation.SSH uses asymmetric key pairs
to implement its secure sessions.The asymmetric key pair consists of two keys: a
private key and a public key. The private key is stored with the owner, and the
public key is distributed freely across the network.The private and public key pair
contains algorithms that complement each other.During authentication,the pub-
lic and the private keys are matched. After successful authentication, the SSH
client is allowed to log on without the need to supply a password.
NNTP
The Network News Transport Protocol (NNTP) is based on the request-response
model. The news delivery is based on the broadcasting technology. Unlike the
messaging protocols, NNTP is delivered to several hosts at a time rather than to
a specific host.NNTP is used to send messages from newsgroups to a Linux com-
puter and from users to the newsgroup.These messages are stored on a newsgroup
or newsnet server. NNTP supports the processes of reading newsgroups, posting
new articles,and transferring articles between news servers.
Linux,like UNIX,is an excellent operating system for Internet servers,including
Web,e-mail,and FTP servers.The vast networking capability of the Linux oper-
ating system makes it a prime candidate to be used as a server in any kind of net-
working environment.Linux supports all of the most common Internet protocols.
Following is a list of some of the protocols supported by Linux: FTP SMNP HTTP POP SMTP Telnet SSH NNTP
Linux has already been widely used and tested on all of these listed protocols.Let
me now discuss each of these protocols.
FTP
File Transfer Protocol(FTP) is one of oldest Internet protocols,and it is still being
used extensively. FTP is a part of the Internet protocol suite that can be used to
transfer files between two computers. FTP works in two modes: text and binary
transfer mode.Many FTP servers such as WS-FTP are available for Linux.Using
FTP,you can access files stored in the disk directory of a remote computer.FTP
is used to do the following: Share files,which might include computer programs and data Indirectly or implicitly use remote computers Shield a user from variations in file storage systems among hosts Transfer data reliably and efficiently
SNMP
Simple Network Management Protocol (SNMP) is a network management proto-
col. It was developed in 1988 to provide a framework for network management.
Some typical purposes for which SNMP can be used are these: Assigning addresses to devices Prioritizing communication Installing software on a network Managing printer queues
Over the years, SNMP has become the standard protocol for internetwork man-
agement.In the manager/agent model,which is adopted by the SNMP protocol,
the processing capability resides on the management system. The management
system is responsible for issuing messages such as
Get,GetNext,and Set.You use
these messages to obtain or store the value of variables.These messages are sent
to the agent responsible for sending a response back to the management system.
HTTP Protocol
HyperText Transfer Protocol(HTTP) is the standard protocol used for transferring
documents on the World Wide Web. HTTP is employed in the client/server
architecture. After a successful connection is established between server and
client,the client can send requests for resources,such as Web pages,on the server.
The server then sends the requested resource back to the client. HTTP operates
over TCP connections, usually at port 80, though this can be overridden and
another port can be used.
POP Protocol
Post Office Protocol(POP) is a messaging protocol that enables users to access their
mailboxes.The POP protocol is based on a client/server model.The messages are
stored in the server.Users download these messages to their computer by using a
POP client, such as Eudora. POP provides for user authentication by authenti-
cating users through passwords.However,passwords are transmitted as clear text,
which means that POP should be used very carefully because the password trans-
mission method is not secure.
SMTP Protocol
Simple Mail Transfer Protocol (SMTP) is a messaging protocol responsible for
delivering mail.It relays mail messages from an SMTP client to the SMTP server
and from one SMTP server to another.In case of delivery failure of mail,the mes-
sages are queued up in the SMTP server.The SMTP server again tries to deliver
these queued messages.Two popular SMTP servers for Linux are Sendmail and
qmail.
Telnet Protocol
The Telnet protocol enables you to remotely log on to a computer on a network.
The Telnet protocol is based on the client/server model.The computer that tries
to connect to the server from a remote location is the client. On the other hand,
the computer to which the request is being made and that allows establishment of
the connection is the server.The connection between the two computers is estab-
lished based on some pre-defined criteria, such as the terminal type to be used.
The username you specify during the connection determines your access on the
destination’s computers files and directories.
SSH Protocol
The Secure Shell (SSH) is a protocol for encrypting TCP sessions over the Inter-
net. The primary use of SSH is remote login. However, it also can be used as a
cryptographic tunnel.This tunnel generated by the SSH can be used for various
purposes,such as copying files,encrypting e-mail connections,and triggering the
remote execution of programs.
Before establishing connection between two computers, SSH connects to the
server, performs secret key negotiation between the two computers, and starts
encrypting the session after successful negotiation.SSH uses asymmetric key pairs
to implement its secure sessions.The asymmetric key pair consists of two keys: a
private key and a public key. The private key is stored with the owner, and the
public key is distributed freely across the network.The private and public key pair
contains algorithms that complement each other.During authentication,the pub-
lic and the private keys are matched. After successful authentication, the SSH
client is allowed to log on without the need to supply a password.
NNTP
The Network News Transport Protocol (NNTP) is based on the request-response
model. The news delivery is based on the broadcasting technology. Unlike the
messaging protocols, NNTP is delivered to several hosts at a time rather than to
a specific host.NNTP is used to send messages from newsgroups to a Linux com-
puter and from users to the newsgroup.These messages are stored on a newsgroup
or newsnet server. NNTP supports the processes of reading newsgroups, posting
new articles,and transferring articles between news servers.
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