IP addresses, ports and NAT
How machines find each other: IPv4 and IPv6 addresses, private networks and masks, ports and services, NAT and port forwarding, and the situations where a service stays unreachable.
- 34 cards
- 3 topics
- Free
The outline, topic by topic
Each topic is weighted the way the exam weighs it.
- Addresses
- Ports
- NAT
A few cards from the deck
IP address: what is it?
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The number that identifies a network interface so packets can be delivered to it
Routers only need it to move a packet toward its destination.
Why was IPv6 created?
- IPv4 was not encrypted
- IPv4 did not work over Wi-Fi
- To replace DNS
- IPv4 addresses were running out given the number of connected devices
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IPv4 addresses were running out given the number of connected devices
About 4.3 billion addresses are not enough to give every device a public address.
IPv4: what is it?
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The IP version with 32-bit addresses, about 4.3 billion addresses
The address pool is exhausted, which made NAT widespread.
How many addresses does the 192.168.1.0/24 network contain?
- 24
- 65,536
- 256
- 1,024
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256
/24 fixes 24 bits out of 32: 8 remain, so 2⁸ = 256 addresses, 254 of them usable by machines.