Chapter 21: The Internet Flashcards
Backbone Router
Major internet routers connected to each other along “backbones” of fiber cable
DSL, with up/down speeds
Digital Subscriber Line - uses telephone connection, always on
1Mbps Up, 3 Mbps down
xDSL can be significantly faster
ADSL vs SDSL
Asymmetric DSL (slow upload, fast download)
Symmetric DSL (equivalent up and down, but expensive)
DSL Microfilter
Placed between line and phone, allows phone devices to function without high-pitched screech of DSL
Cable internet speeds
5-35+ Mbps Upload
15-200 Mbps Download
FTTN vs FTTP
Fiber to the Node - Goes to box in neighborhood, then coax line to house ethernet
Fiber to the Premises - fiber all the way, links to an optical network terminal in house (ONT)
Both provide Gbps speeds
WISP
Wireless Internet Service Provider - utilizes point-to-point connections
WWAN
Wireless Wide Area Network - internet through your mobile/cell connection
Tethering and using a hotspot
LTE
Long Term Evolution (major market share currently); aka 4G
100Mbps up, 1Gbps down
4G and 5G can easily replace wired network speeds as long as coverage is available
NAT
Network Address Translation
When a router represents a LAN with a singular IP address, basically your public address
Router Configuration Settings
UPnP (Universal Plug and Play) - lowers security, but allows devices to easily communicate with each other
Always change default username and password
May wish to set a static IP
DNS
Domain Name System - UDP - Port 53
DHCP
Dynamic Host Configuration Protocol - UDP - Port 67, 68
LDAP
Lightweight Directory Access Protocol (queries a database) - TCP - Port 389
SNMP
Simple Network Management Protocol (endpoint management) - UDP - Port 161, 162
Can gather insane amount of data if queried, remote configuration and monitoring
SMB/CIPS
Server Message Block/Converged Internet Protocol Service (folder/file sharing) - TCP port 445 - UDP port 137, 138, 139
NetBIOS/NetBT
BIOS - TCP port 137, 139 - UDP port 137, 138
HTTP/HTTPS
Hypertext Transfer Protocol/Hypertext Transfer Protocol Secure - port 80/port 443
FTP/SFTP
File Transfer Protocol/Secure File Transfer Protocol - port 20, 21/port 22
IMAP/POP3
Internet Message Access Protocol/Post Office Protocol - incoming email - port 143/port110
SMTP
Simple Mail Transfer Protocol - outgoing email - port 25
Telnet
Terminal emulation - port 23 (very insecure)
SSH
Secure Shell Protocol - encrypted terminal emulation - port 22
RDP
Remote Desktop Protocol - port 3389
Browser Security
Verify browsers through hashing and or/code signing
Checksum runs a file through hashing, essentially putting a fingerprint on it. Run the program through that to see if the fingerprints match with the official
Code signing verifies digital certificates/signatures
Certificate Authority (CA)
Verifies that a site is trustworthy
Data stored in Browsers
history
scripts (cookies, temp storage)
settings per site
form data
cached copies (clearing your cache will increase your browser speed)
Internet Options applet
Legacy applet from IE days
Basic IE config
Security - can set configs for zones, can relax security for intranet sites
privacy - cookies etc, blocked vs unblocked sites
content - tweak autocomplete, block sites
connections - set up VPN, broadband vs dialup, LAN settings
Proxy Server
connections to internet pass through 1 protected computer, requests go to this server, rather than sent directly to the web
Types of Remote Access
Telnet - should only use within own LAN, unprotected connection
SSH - encrypted tunnel, can also move files (called tunneling)
VNC - Virtual network computing
MSRA - Microsoft Remote Assistance (remote control)
Endpoint Management Server
The endpoint for a VPN service
Start|”VPN”|VPN Settings|Add a VPN
RMM
Remote Management and Monitoring software - monitor and manage health of both wireless and wired devices
ICS
Industrial Control System - embedded system for managing a factory
UDP vs TCP examples
UDP (connectionless protocols) - TFTP (trivial FTP - port 69) and DHCP
TCP (connection oriented) - HTTPS and SSH (SFTP uses SSH)
SCADA
Supervisory Control and Data Acquisition - for wide areas, help operate system safely when outages occure
Steps to Troubleshoot Connectivity
1) Try other sites
2) Try other browser
3) try ping
4) try ipconfig /flushdns
5) Run troubleshooter
6) Try another DNS connection
QoS
Quality of Service, basically prioritizes traffic
