1.3 NETWORK PROTOCOLS
• What are protocols - sequences that computers must follow when sending and receiving information. These agreed methods make sure that information is sent and received correctly.
• Why do we need protocols - Without some agreement about what information is arriving over the network, it would just seem like garbage. This would be like somebody suddenly sending stock market numbers by morse code without telling us what it is.
1.3.1 Mail Transfer Protocols
• Popular email methods include,
SMTP (Simple Mail Transfer Protocol) - for sending mail
POP3 - for retrieving mail
IMAP - for retrieving mail
• Note that the campus mail system ‘ccmail’ is not standard. It will communicate with other mail programs using standard services, but internally special software must be used. Soon ccmail will be available using the POP3 standard, so that you will be able to view your ccmail using Netscape, but some of the features of ccmail will not be available.
• Listservers allow you to send mail to a single address, and it will distribute it to many users (IT can set this up for you).
220.127.116.11 - Attachments
• We can attach files to our email. It is normally stored using the MIME format.
• These formats will allow the files to travel with the text of the message, and then be extracted by the receiver.
18.104.22.168 - Mail Lists
• We can set up mail servers that will accept a mail message addressed to the group, and then distribute it to the individual users.
1.3.2 FTP - File Transfer Protocol
• This is a method for retrieving or sending files to remote computers.
• These are informal groups (from local to international). The groups allow ongoing discussions between many individuals.
• You can get newsgroups set up for your courses to allow student discussions (just ask the IT people). This is a good alternative to chat groups.
• Notice that newsgroups have messages spanning a period of time. If the time period for message storage is the length of the term, the group will act as a permanent record of discussions.
1.3.4 HTTP - Hypertext Transfer Protocol
• This is the protocol used for talking to a web server.
• chat groups allow on-line conversations. If we compare these to newsgroup - these are realtime by nature.
• Allows us to share files stored on a server.
• Security problems usually arise through protocols. For example it is common for a hacker to gain access through the mail system.
• The system administrator is responsible for security, and if you are using the campus server, security problems will normally be limited to a single user.
• Be careful with passwords, this is your own protection again hacking. General rules include,
1. Don’t leave yourself logged in when somebody else has access to your computer.
2. Don’t give your password to anybody (even the system administrator).
3. Pick a password that is not,
- in the dictionary
- some variation of your name
- all lower case letters
- found in television
- star trek, the bible
- pet/children/spouse/nick names
- swear words
- colloquial phrases
4. Watch for unusual activity in you computer account.
5. Don’t be afraid to call information technology and ask questions.
6. Don’t run software that comes from suspect or unknown sources.
7. Don’t write your password down or give it to others.