1. Electronic Mail E-mail POP mail server IMAP mail transport server
is a system for sending messages or files to the accounts of other computer users
Senders and recipients may be on the same or different computer system
like regular postal mail, every user on the network has a private mailbox
POP mail server
IMAP mail transport server

2. E-mail URL E-mail URL Header Body has the format “mailto:user-address”
lets you send messages to a particular person
Header
to whom the message is sent
who the message is from
what the subject is
Body
is the text of the message

3. E-mail - commercial services
America On-line
Applelink
BITNET
CompuServ
MCIMail
Netcom
Microsoft Network

4. Pros and Cons gets a message from one point to another very quickly
cheaper than a telephone for instant long-distance communication
the sender can send it when it’s convenient
recipients can read it when it’s convenient
no matter how quick a message may arrive, it may be late if the receiver fails to check the on a regular basis
easy to distribute messages to multiple receivers
because it is easy, junk mail is sent to a large number of people, chain letters can flood the network
security is low in communication
careless comments can lead to misunderstanding

5. Guidelines Never send e-mail that you wouldn’t want to become public
keep length of lines short
don’t use abusive, harassing or bigoted words
Use both upper and lowercase characters
Be careful with sarcasm or jokes
Read the message before sending
When responding to message with multiple recipients, be very careful to whom you are responding

6. Email on Cerritos Alpha
logon
At the $ prompt, type (not case sensitive in Cerritos campus environment)
Type “dir newmail” to check for new mails (unread mails)
Type “1” to read mail #1, “2” to read mail #2
Type “dir mail” to look at read mails (old mail)
Type “reply” or “forward” to reply or forward the message you are reading
Type “delete 1-6” to delete the first 6 mails (be careful which folder you are in, the mail folder or the newmail folder)

7. Email address Username@hostname.domainname
Top level domains - North America (organizational)
Top level domains - Country (geographical)

8. Organizational domain name
If geographic location is not specified, it is assumed to be the United States
COM Commercial organizations
EDU Educational and research institutions
GOV Government agencies
MIL Military agencies
NET Major network support centers
ORG Other organizations
INT International organization

9. Geographical domain name
AQ Antarctic
AR Argentina
AT Austria
AU Australia
BR Brazil
CA Canada
CH Switzerland
CL Chile
DE Germany
ES Spain
FR France
HK Hong Kong
KR Korea
MX Mexico
PR Puerto Rico
PT Portugal
SG Singapore
TW Taiwan
UK United Kingdom
US United States
VE Venezuela
ZA South Africa

10. Domain name and IP address
unique range of address is assigned to network site
one address for each device on the network
each address is a number called an ‘Internet Protocol’ (IP) address
a series of four number separated by periods (dots)
e.g
IP address is hard to remember by human
Domain name
jupiter.willamette.edu is the domain name for IP address

11. Domain name and IP address
michael.ai.mit.edu
the Interent host michael is in the domain called ai, which is in the domain mit which is an educational institution (edu)
domain names are divided into various levels
last word in the domain name is the top-level domain, which can be geographic location/countries or organizational in North America

12. IP (Internet Protocol) address
4 numbers separated by periods (“dots”)
= world.std.com
= alpha1.cerritos.edu
Domain naming
machine.subdomain.organization.domain
fred.mfg-div.galacto.com
computer subdomain domain
Specific General

13. Internet Address examples
Domain examples
msc.cerritos.edu
gold.cerritos.edu
calstate.edu
lbcc.cc.ca.us
jabber.wock.com
flack.cs.laputa.edu
dims.demon.co.uk
north-high.menlo.k12.ca.us

14. Internet User address examples

15. Domain name
The second to last word in domain name is descriptive reference
e.g..
stjude.edu educational institution name St. Jude’s
nwnet.net network service provider called NWNet
apple.com a company called Apple
jupiter.willamette.edu
mercury.willamette.edu are both computers in the Willamette University network.