76 lines
1.8 KiB
Markdown
76 lines
1.8 KiB
Markdown
---
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id: 07. IPv4 Addressing (Part 1)
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aliases: []
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tags: []
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---
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# IPv4 Addressing (Part 1)
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## [[OSI Model]]
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- Provides connectivity between end hosts on different networks
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(ie. outside of the [[LAN]])
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- Provides logical addressing [[IP addresses]]
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- Provides path selection between source and destination
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- [[Routers]] operate at Layer 3
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## IPv4 Header
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IP addresses are 32 bits long
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Class A
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192.168.1.254/24
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192.168.1. = network portion (part of the same network)
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254 = host portion (different machine)
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Class B
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154.78.111.32/16
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154.78 = network portion
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111.32 = host portion
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Class C
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12.128.151.23/8
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12 = network portion
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128.151.23 = host portion
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## [[IPV4]] address classes
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| Class |First octet | numeric range| Prefix Length |
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| ----- | ---------- | --------------| /8 |
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| A |0xxxxxxxx | 0-127 | /16 |
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| B |10xxxxxxx | 128-191 | /24 |
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| C |110xxxxxx | 192-223 | |
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| D |1110xxxxx | 224-239 | |
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| E |1111xxxxx | 240-255 | |
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class D are reserverd for Multicast addresses
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class E are reserved for expermital
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end of the class A is 126
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127 are reserved for loopback addresses
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## Loopback addresses
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- Address range 127.0.0.0 - 127.255.255.255
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- Used to test the 'network stack' (think OSI, TCP/IP model) on local device
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## Netmask
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Class A: /8 255.0.0.0
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Class B: /16 255.255.0.0
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Class C: /24 255.255.255.0
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Host portion of the address is all 0's = Network Address
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the netowrk address cannot be assigned to a host
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Host portion of the address is all 1's = Broadcast address Address
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The Broadcast address cannot be assigned to a host
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## Review
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- Network portion / host portion of IPv4 address
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- IPv4 classes
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- Prefix lengths / netmasks
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- Network address / broadcast addresses
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