| Lesson 11 || A survey of common services |
| Objective || Examine other network services that may be available on UNIX machines. |
Survey of Common Services
There are a variety of network services available on UNIX machines. Most are independent of UNIX, and may be used across the Internet. Below is a listing of common services:
You can use the following commands as per your UNIX operating systems to start or stop networking service.
HP-UX Unix start / stop / restart networking service
# /sbin/init.d/net stop
# /sbin/init.d/net start
# /sbin/init.d/hostname start
- Trivial services
- FTP Bulk Data Transfer Service
- Berkeley r commands (rlogin, rsh)
- Domain Name Service (DNS)
- Simple Mail Transfer Protocol(SMTP)
- Network News Transfer Protocol (NNTP)
- Hypertext Transfer Protocol (HTTP)
(NNTP) Network News Transfer Protocol
The (NNTP) Network News Transfer Protocol is an application protocol used for transporting Usenet news articles between news servers and for reading and posting
articles by end user client applications. Brian Kantor of the University of California, San Diego and Phil Lapsley of the University of California, Berkeley authored RFC 977, the specification for the Network News Transfer Protocol, in March 1986.
Usenet was originally designed based on the UUCP network, with most article transfers taking place over direct point-to-point telephone links between news servers, which were powerful time-sharing systems.
Readers and posters logged into these computers reading the articles directly from the local disk.
As local area networks and Internet participation proliferated, it became desirable to allow newsreaders to be run on personal computers connected to local networks.
The resulting protocol was NNTP, which resembled the Simple Mail Transfer Protocol (SMTP) but was tailored for exchanging newsgroup articles.
A newsreader, also known as a news client, is a software application that reads articles on Usenet, either directly from the news server's disks or via the NNTP.
The well-known TCP port 119 is reserved for NNTP and TCP port 433 (NNSP) may be used when doing a bulk transfer of articles from one server to another.
When clients connect to a news server with Transport Layer Security (TLS), TCP port 563 is often used. This is sometimes referred to as NNTPS.
Alternatively, a plain-text connection over port 119 may be changed to use TLS via the STARTTLS command.
Talking to Servers using Telnet