Fall2020-CEG3120-ExamReview

Exam review for CEG3120 for Fall 2020

Recommendation: since filling out every topic would get ugly, I recommend creating a separate page for each topic.

Midterm Review Outline for Fall 2020

Git / GitHub

• add
• commit
• push
• pull
• clone vs fork
• branch
• checkout
• merge conflicts
• stashing
• clean vs reset
• GitHub issues
• GitHub pull requests

Linux

• file & directory permissions
• ownership & groups
• PATH manipulation
• File System - what to expect in root folders
  • /etc/
  • /var/
  • /proc/
  • /dev/
  • /bin/ & /sbin/
  • /boot/
  • /home/
• User / group management
  • Configuration files to note:
    • /etc/passwd , /etc/group, /etc/shadow
• Service management
  • systemctl
• System logs
  • Log files can cause disk bloat
  • journalctl
    • Find user associated logs
    • Find service related logs

IT Knowledge

• Partition tables, partitions, filesystems
• Mounting partition(s)
  • Role of /etc/fstab
• RAID 0, 1, 5, 6
  • Given situation, which RAID would you recommend?
• Backups & Imaging
• cronjobs
  • Where to add a cronjob - crontab
  • Format of a cronjob

Networking

• dotted quad (format of IPv4 address)
• host
• subnet
  • Network prefix
  • Subnet mask
  • CIDR notation (substitute for long form subnet mask)
• gateway
• routing
  • Read a routing table for where traffic will be routed
• MAC addresses
  • arp table associates MAC with IP
• Hardware interface names (common)
  • eth0, wifi0 / wlan0, lo
• DNS
  • Local hostname resolution
    • Role of /etc/hosts
    • Role of /etc/resov.conf
• Ports (common)
  • 22 (SSH), 80 (HTTP), 443 (HTTPS)
  • Read output of netstat with flags (-n -t -l)
• What an IP address tells you about the network:
  • Private network prefixes:
    • 10.0.0.0/8
    • 192.168.0.0/16
    • 172.16.0.0/12
  • Local network prefixes:
    • 127.0.0.0/8
• Router (as separate hardware):
  • NAT
  • DHCP
• Firewall
  • INPUT, OUTPUT, FORWARD chains
  • Can be managed at router level or host level
  • Host level management in Linux: iptables
  • Packet is blocked by first rule that matches in chain
• Forward proxy vs VPN
• Reverse proxies:
  • Caching
  • Load balancing (web servers)
    • Monitor services?
    • Allocation strategies
    • Connection maintainence
    • Session persistence

System level process control

• Background processes
  • move to background
  • bring to foreground
• User generated process independent of terminal connection
  • nohup
  • screen

Bash

• IO redirection
• Different types of quotes
• ~/.bashrc vs ~/.profile
• source vs ./ vs running script using name
• Variables and accessing variable values
• Use arguments
  • In a script
  • In a script function
• Conditionals (using the test command)
• if statements
• functions
• Regular expressions

SSH

• keys (private vs public)