vault backup: 2023-03-20 09:24:23

content/notes/06-network-system-administration.md

@@ -0,0 +1,91 @@
+---
+title: "06-network-system-administration"
+tags: 
+- lecture
+- cosc301
+---
+
+
+security awareness
+- physical and network attacks
+- [[security]]
+
+Computer/Internet hazards 
+- SPAM/UCE (Unsolicited Commercial Email) 
+- Phishing 
+- Disk crashes/data loss 
+- Loss of services due to outage 
+- TCP/IP spoofing and sniffing (privacy) 
+- Pornography 
+- Ignorant users 
+- Grumpy (former) employees 
+- Administrators of the untrained kind
+
+broken symlink
+- broken symlilnk/softlink can be a risk
+- If it is pointing to a location that is accessible by an attacker, it ends up retrieving a file belong to the attacker. 
+- If it is a web server, you end up retrieve and present the attacker’s information. 
+- Solution: NO_FOLLOW flag to stop following the symlink.
+
+Roles in network community
+- Important roles include users, hosts, network components e.g. routers and operating systems. 
+	- Users - should be trained to be aware of the community. Human beings are usually the weakest link. 
+	- Host machines - should be allocated different tasks on different server machines 
+	- Routers/gateways 
+	- affect network security and performance 
+	- OS - have different pros and cons 
+	- UNIX/Linux, Windows, MAC OS, Netware
+
+
+Host Management 
+- Shutting down a host 
+	- Turn off the power? 
+	- Should use command shutdown 
+	- shutdown -h time halt the system. time can be now. 
+	- shutdown -r time reboot the system 
+- Log files and audits: health barometer of a host 
+	- syslogd: a daemon for logging messages. Its configuration file is /etc/syslog.conf 
+	- dmesg: check kernel messages 
+	- lastlog: check the last login time of every user 
+	- syslog under /var/log: the log file of the system 
+	- They should be rotated regularly
+
+User Management 
+- User account 
+	- Includes all the files, resources, and info belonging to one user. For commercial systems, it may include billing info. 
+- Create a new account 
+	- adduser 
+	- Account info: username, password, user id, group id, full name of user, home directory, login shell 
+	- In the /etc/passwd file, 
+		- Amber:x:1000:100:Amber Dawn:/home/amber:/bin/bash 
+	- Check after adding
+- Involved files 
+	- /etc/passwd, /etc/group, /etc/shadow 
+	- In /etc/shadow, 
+	- Chloe:$2a$05$wa7xVOqOH4lVOrh.qa9ivSX0G0QUCFqbk11YV6:14743:0:99999:7::: 
+	- Username:encrypted password:last password change:minimum:expiration:warning:disabled:diabled date:reserved 
+- User login environment 
+	- .bash_profile, .bashrc, /etc/profile 
+	- Place global files such as profile under /etc 
+- Other scripts can be referred in it 
+	- Use env/set to check/set your environment 
+- Paths and prompts 
+	- Keep a copy of your shell scripts (initial setups) in order to survive them from upgrade of OS/software 
+- For more detailed info, man bash
+- Password 
+	- Very important for security 
+	- Should not be names of persons, books, places, your computer, nor your phone number, birthday, car registration plate, login name, words in dictionaries, keyboard sequence 
+	- Should be composed of letters (lower and upper cases), digits, and special characters like $,@ 
+	- Refer to http://en.wikipedia.org/wiki/Password_strength 
+	- passwd imposes similar rules to make passwords secure. 
+	- Change frequently 
+- User id and group id 
+	- Users should be divided into groups for security reasons, e.g. students, staff, admin 
+	- Special users/groups: nobody, mail, ftp 
+- addgroup 
+	- In /etc/group, 
+	- video:x:33:hzy,paul,kai 
+	- Group name:password:group id;list of members
+
+- Remove a user: deluser – The relevant lines from /etc/passwd, /etc/group, and /etc/shadow will be removed. – It is a good idea to first disable the account before you start removing stuff 
+- Disable a user temporarily – A better way when you are not sure if a user will come back – Way 1: Put an * in the password field of /etc/shadow – Way 2: use passwd -{l|u} username – Way 3: Change the login shell to a script file

content/notes/07-system-installation.md

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+---
+title: "07-system-installation"
+tags: 
+- lecture
+- cosc301
+---
+
+

content/notes/cosc-301.md

@@ -33,5 +33,5 @@ https://www.cs.otago.ac.nz/cosc301/schedule.php
 - [x] [[04-scripting-techniques]]
 - [x] [[05-filesystems]]
 - [[06-network-system-administration]]
-- 
+- [[07-system-installation]]
 # Info

content/notes/cosc-342.md

@@ -22,7 +22,7 @@ tags:
 - [x] [[03-2d-transforms]]
 - [[04-mosaicing]]
 - [x] [[05-feature-description-and-matching]]
-- [ ] [[06-homographies]]
+- [x] [[06-homographies]]
 
 # Info
 

content/notes/info-305.md

@@ -17,9 +17,9 @@ tags:
 # Lectures
 - [x] [[01-intro-to-305]]
 - [x] [[02-intro-pervasive-and-ubiquitious]]
-- [[03-intro-AR-dev]]
+- [x] [[03-intro-AR-dev]]
-- [[04-lens-studio]]
+- [x] [[04-lens-studio]]
 - [x] [[05-pervasive-ubiquitious-2]]
-- [[06-challenges-for-ubicomp-and-intro-to-sensors]]
+- [x] [[06-challenges-for-ubicomp-and-intro-to-sensors]]
 
 # Info