Network Configurations Flashcards
What is the structure of an IPv4 address?
An IPv4 address is written in dotted-decimal notation, consisting of four octets (e.g., 192.168.1.4). Each octet is 8 bits, making the full address 32 bits.
How is an IPv4 address represented in binary?
Each octet in an IPv4 address is converted to an 8-bit binary number. For example, 255 in decimal equals 11111111 in binary.
What is the role of a subnet mask in IPv4?
A subnet mask divides an IP address into the network and host portions, helping to identify the network and available hosts.
What are the IPv4 address classes and their ranges?
Class A: 1-127 (default mask /8)
Class B: 128-191 (default mask /16)
Class C: 192-223 (default mask /24)
Class D: 224-239 (multicast)
Class E: 240-255 (experimental)
What is CIDR notation, and how does it simplify subnetting?
CIDR (Classless Inter-Domain Routing) uses a slash notation (e.g., 192.168.1.4/24) to define the network portion of an IP address, providing more flexible subnetting.
What are the common private IP address ranges?
Class A: 10.0.0.0 – 10.255.255.255
Class B: 172.16.0.0 – 172.31.255.255
Class C: 192.168.0.0 – 192.168.255.255
What is the difference between public and private IP addresses?
Public IPs are assigned globally and can be accessed over the internet, while private IPs are used within a local network and cannot be routed over the internet.
What is the loopback address in IPv4?
The loopback address is 127.0.0.1, used for testing network protocols on the local machine.
What are the four steps of the DHCP process (DORA)?
- Discover: Client requests an IP.
- Offer: DHCP server offers an IP.
- Request: Client requests the offered IP.
- Acknowledge: Server confirms the assignment.
What is DHCP reservation?
DHCP reservation ensures that a device always receives the same IP address based on its MAC address.
What is APIPA and when is it used?
APIPA (Automatic Private IP Addressing) assigns an IP in the 169.254.x.x range when a DHCP server is unavailable.
What is the purpose of DNS?
DNS translates human-readable domain names (e.g., www.example.com) into numeric IP addresses for easier access to network services.
What is the purpose of the A record in DNS?
The A record maps a domain name to an IPv4 address.
What does TTL mean in DNS?
TTL (Time to Live) specifies how long a DNS record should be cached by DNS resolvers to reduce repeated lookups.
What is a VLAN and why is it used?
A VLAN (Virtual Local Area Network) segments a network into multiple broadcast domains, improving security and efficiency by isolating traffic.
What is VLAN trunking?
VLAN trunking uses 802.1q to allow multiple VLANs to share a single physical link between switches while preserving logical separation.
What is a VPN and why is it used?
A VPN (Virtual Private Network) extends a private network over a public network, allowing secure access to data as if directly connected to the private network.
What is a site-to-site VPN?
A site-to-site VPN connects two separate office networks, allowing encrypted data to travel over the public internet.
What is the difference between full tunnel and split tunnel in VPN?
Full Tunnel: Routes all traffic (internet and internal) through the VPN.
Split Tunnel: Routes only corporate traffic through the VPN, leaving other traffic to go directly to the internet.
What is the difference between inbound and outbound ports?
Inbound ports listen for connections (e.g., web servers on port 80), while outbound ports are used by clients to initiate connections (often random high numbers).
What are the three main port ranges and what do they represent?
Well-Known Ports (0–1023): Common protocols like HTTP (80), FTP (20/21), SSH (22).
Registered Ports (1024–49151): Proprietary protocols like RDP (3389).
Dynamic/Private Ports (49152–65535): Used by applications for temporary connections.
Which common protocols use the following ports: 80, 443, 22, 53, 3389?
HTTP (80), HTTPS (443), SSH (22), DNS (53), RDP (3389).
What is the main difference between TCP and UDP?
TCP is connection-oriented and reliable, ensuring data arrives in order, while UDP is connectionless and unreliable, with no guarantee of data delivery.
What are the key characteristics of TCP?
Reliable with retransmission of lost segments.
Uses a three-way handshake (SYN, SYN-ACK, ACK).
Ensures data integrity (e.g., HTTP, SSH).
What are the key characteristics of UDP?
Unreliable, with no retransmission of lost packets.
No sequence or flow control.
Suitable for applications that can tolerate some data loss (e.g., VoIP, streaming).
What are common use cases for TCP?
Web browsing (HTTP/HTTPS), remote login (SSH), and email (SMTP), where data integrity is essential.
What are common use cases for UDP?
Video/audio streaming, VoIP, gaming, and some network protocols (e.g., DHCP, TFTP), where speed is more important than reliability.
How does flow control work in TCP?
TCP uses windowing to manage the flow of data, avoiding congestion and ensuring smooth transmission.
What is a simple analogy to understand TCP and UDP?
TCP: Like certified mail, ensuring every piece of data reaches its destination.
UDP: Like sending a postcard, with no guarantee of delivery.
What are the port numbers for FTP, and what is its purpose?
FTP uses ports 20 and 21 for unencrypted file transfers.
What port does SSH use, and what is its purpose?
SSH uses port 22 for secure command-line access.
What port does Telnet use, and what is its purpose?
Telnet uses port 23 for unsecure command-line access.
What port does SMTP use, and what is its purpose?
SMTP uses port 25 for sending emails.
What port does DNS use, and what is its purpose?
DNS uses port 53 for name-to-IP mapping.
What are the port numbers for DHCP, and what is its purpose?
DHCP uses ports 67 and 68 for dynamic IP allocation.
What port does HTTP use, and what is its purpose?
HTTP uses port 80 for insecure web browsing.
What port does POP3 use, and what is its purpose?
POP3 uses port 110 for basic email retrieval.
What port numbers does NetBIOS use, and what is its purpose?
NetBIOS uses ports 137-139 for Windows file and printer sharing.
What port does IMAP use, and what is its purpose?
IMAP uses port 143 for advanced email retrieval with synchronization.
What are the port numbers for SNMP, and what is its purpose?
SNMP uses ports 161 and 162 for network management.
What port does LDAP use, and what is its purpose?
LDAP uses port 389 for directory services.
What port does HTTPS use, and what is its purpose?
HTTPS uses port 443 for secure web browsing.
What port does SMB use, and what is its purpose?
SMB uses port 445 for Windows file and printer sharing.
What port does RDP use, and what is its purpose?
RDP uses port 3389 for graphical remote desktop access.
