Overview
Summarizing ambiguous terms related to networks.
IPv4
- Internet Protocol version 4
- A type of IP (Internet Protocol)
- A protocol positioned at the network layer in the OSI reference model
- Has a 32-bit address space
- 2^32 = 4,294,967,296 total IPv4 IP addresses
- Has been depleting with the spread of the Internet
cf.
IPv6
- Internet Protocol version 6
- A type of IP (Internet Protocol)
- A protocol positioned at the network layer in the OSI reference model
- Has a 128-bit address space
- 2^128 = approximately 340 undecillion (1 undecillion is 1 trillion * 1 trillion * 1 trillion) total IPv6 IP addresses
- IPSec (which encrypts IP packet data) is a standard feature
- Optional in IPv4
cf.
NAT
- A technology that converts one IP address to another
- Used in routers and wireless LAN access points
- Static NAT
- Converts IP addresses in a 1:1 manner
- Mainly used for converting global IPs to private IPs
- Dynamic NAT
- Converts IP addresses in a 1:N manner
- Examples of NAT (NAPT) usage
- When accessing the Internet from a network using private IP addresses
- When externally publishing a server with a private IP address within a company
- When there are duplicate IP addresses within a company
cf.
- wikipedia - Network Address Translation
- www.infraexpert.com - NAT (Network Address Translation)
locked.jp- milestone-of-se.nesuke.com - 【Illustration】Understanding NAT for Beginners: Types ~ Static/Dynamic NAT/NAPT (PAT), Security Benefits/Drawbacks ~
NAPT
- A technology that converts one IP address to another
- Used in routers and wireless LAN access points
- The implementation in Linux is called IP masquerade
- Static NAPT
- Converts one IP address + TCP/UDP port number to another IP address + port number in a 1:1 manner
- Dynamic NAPT
- Converts IP addresses in a 1:N manner
- Converts a source IP address to one global IP in an N:1 manner
- Converts the source port number to an unused port number
cf.
- wikipedia - Network Address Translation
locked.jp- milestone-of-se.nesuke.com - 【Illustration】Understanding NAT for Beginners: Types ~ Static/Dynamic NAT/NAPT (PAT), Security Benefits/Drawbacks ~
CIDR
- Classless Inter-Domain Routing
- A technology for assigning and routing IP addresses without using classes
- A mechanism to reduce the bloat of routing tables in routers on the Internet
- The method of assigning and routing IP addresses by class is not scalable
- To address this issue, standards defining the allocation method of IP address blocks were introduced (RFC1518, RFC1519, etc.)
- Allows changing the size of the allocated block by specifying the size of the network part of the IP address using a variable-length subnet mask in bits
- CIDR notation
- 192.168.1.0/24
cf.
Subnet Mask
- A number used to identify the network address and host address within an IP address
- For IPv4, it is 32 bits
- For IPv6, it is 128 bits
cf.
DHCP
- Dynamic Host Configuration Protocol
- A communication protocol used in IPv4 networks
- Automatically assigns the configuration information necessary for computers to connect to the network
- Used in both IPv4 and IPv6, but considered a different protocol due to differences in protocol details
- Positioned at the application layer in the OSI reference model
cf.
Link-Local Address
- An address that is valid only for communication within the network segment or broadcast domain (the range of the network where broadcasting can occur; broadcasting sends the same data to all users on the same network)
- A special IP address that is self-assigned and used in networks without a DHCP server
cf.
ICMP
- Internet Control Message Protocol
- A protocol for forwarding error notifications and control messages for the IP protocol
- Used to check the communication status
- Used in the ping command
cf.
L4 Load Balancer
- L4 → Transport Layer
- Load balancing based on IP address and port number is possible
cf.
- faq.support.nifcloud.com - Please tell me the difference between L4 Load Balancer and L7 Load Balancer (Pulse Secure Virtual Traffic Manager)
- www.kimullaa.com - Differences between L7 Load Balancer and L4 Load Balancer
L7 Load Balancer
- L7 → Application Layer
- Load balancing based on URL and HTTP headers is possible
cf.
