Portable Computing Security & More–NETWORKING, SECURITY, & MORE ESSENTIALS—CompTIA A+ (220-1001) A-PLUS Certification Prep Course Notes

Portable Computing Security & More

The Internet

Telnet & SSH
- The Telnet and the Secure Shell (SSH) protocols provide command line access to remote systems.
- Telnet runs on TCP port 23; SSH runs on TCP port 22.
- Telnet is unencrypted; SSH is encrypted.
- Telnet uses Port 23.
- Telnet:
  - One of the earliest application protocols; allows access to another computer;
  - A remote command line tool; a powerful tool; allows you to get to the command line on another comuter.
  - To access a Telnet server, you need a Telnet client (similar to how in order to access a web server you need a web client, aka–web browser).
  - Putty is a popular Telnet client.
- Telnet lacks encryption and offers NO SECURITY!!!
- SSH–uses port 22 (SSH is like Telnet’s encrypted big brother!)
- SSH gets you to a command line but with end-to-end encryption!
  - Only use SSH when connecting over the internet (outside of a private network)

Remote Desktop Connections
- Windows uses Remote Desktop Protocol (RDP) for remote connectivity; uses port 4389.
- Use Virtual Network Computing (VNC) protocol for connecting to Linux & Mac systems.
- Try TightVNC to use VNC from a Windows system.

The World Wide Web
- The WWW uses either the HTTP (Hypertext Transfer Protocol) or HTTPS (HTTP Secure) protocols.
- HTTP uses port 80 and is NOT secure.
- HTTPS uses port 443 and uses certificates to make a secure connection.
- Make sure to recognize typical certificate errors!
- SSL (Secure Sockets Layer) (Note: SSL & SSH are two separate things!)
- TLS (Transport Layer Security)
- Tools:
  - neverssl.com
  - badssl.com
  - Gives examples of bad certificates.

Troubleshooting Internet Connections
- Network troubleshooting, check physical connectivity first!
- Run ipconfig /all from the CLI to get a ton of network info.
- Run traceroute (Linux/Mac)/tracert (Windows) to test Internet connectivity (before you have problems!)
  - ex: traceroute www.google.com
- Run ping to test connection between two systems (plus DNS).
- KNOW YOUR NETWORK! (Know your network ID, know what your router is, & know what your DNS server is!) (Run ‘ipconfig’ for these!)
- Many connectivity problems can be fixed with just ping, traceroute, & ipconfig!

Power Management: Laptops
- ACPI (Advanced Configuration and Power Interface).
  - Built-in functions; built into the CPU; power functions.
- ACPI level 0 is enabled, but unused.
- ACPI level 3 is sleep mode. RAM is powered.
- ACPI level 4 is hibernation. RAM data is copied to mass storage.
- All operating system provide power management utilities.
- AC Adapter
  - many use Vendor Specific Power Ports (proprietary).

Mobile Devices & Email
- CDMA phones do not use SIM cards. GSM phones use SIM cards.
- Screen locks prevent others from accessing your phone using fingerprints, pin codes, passwords or facial recognition.
- Multifactor authentication (MFA or 2FA) means to use more than one way to authenticate.
- Authenticator apps add on extra layer of security.
- Location apps like “Find My Phone” help locate lost devices.
- MDM (Mobile Device Management)
- BYOD (Bring Your Own Device)
- COPE (Corporate Owned Personally Enabled)