2.6 - Explain common network configuration concepts. Flashcards
IP Addressing
IPv4 is the primary protocol for everything we do.
IPv6 is slowly appearing.
Static IP Addressing
With DHCP your IP address with occasionally change.
You may not want your IP address to change.
- Printer, Server etc.
Hence why Static IP address is necessary.
Disabling DHCP on the device means you will have to configure the IP address manually.
Configure a IP reservation on the DHCP server, associate a specific MAC address with an IP address.
Requires additional Administration.
DHCP or Dynamic IP Addressing
Dynamic Host Configuration Protocol
Automated configuration of IP address, subnet mask and other options.
Dynamic > Pooled
- IP addresses are assigned in real time from a pool.
_______________________
DORA THE EXPLORER
Discover:
Client work station does not have an IP so it sends a broadcast to UDP/67.
Broadcast will be received by the DHCP servers configured on the network.
Offer:
All configured DHCP servers on the network will examine the request.
If the server has an IP address that is available it will make an offer to the client workstation using a broadcast to UDP/68.
Request:
Client work station chooses first offer that was received.
Sends broadcast over UDP / 67 to request this IP Address.
Acknowledge:
Formal acknowledgement sent over UDP/68 to workstation.
Client workstation can configure its IP address.
APIPA
Automatic Private IP Addressing.
A link-local address
No forwarding by routers
IETF has reserved 169.254.0.1 through 169.254.255.254
First and last 256 addresses are reserved
Functional block of 169.254.1.0 through 169.254.254.255.
Automatically assigned
Uses ARP to confirm the address isn’t currently in use
IPv6 link-local addresses
A non-routable local network address.
Will only work on the local subnet.
Required on every IPv6-enabled interface
You may see many IPv6 addresses per interface
DNS
Domain Name System.
Converts names to IP addresses.
Usually 2 DNS servers in IP configuration because it is important.
IPv4
Internet Protocol Version 4.
Example IPv4 address: 192.168.1.165 .
- 32 bit, 4 byte address.
Since one byte is 8 bits, the max decimal val for each byte is 255.
Every device needs a unique IP address
IPv6
Internet Protocol Version 6.
128 bit address.
DNS is very important for IPv6 addresses.
340 undecillion addresses available.
First 64 bits of address is generally the network prefix.
Last 64 bits is then the hot network address.
Default Gateway
Default gateway, e.g. 192.168.1.1
The router that allows you to communicate outside of your local subnet.
The default gateway must be an IP address on the local subnet.
Subnet Mask
Subnet mask, e.g., 255.255.255.0
Used by the local device to determine its subnet.
The subnet mask isn’t (usually) transmitted across the network
SSL VPN
Secure Sockets Layer Virtual Private Network.
Uses common SSL/TLS protocol.
Avoids running into most firewall issues.
No big VPN clients.
Usually remote access communication.
Authenticate users.
No requirement for digital certificates or shared passwords (like IPSec).
Can be run from a browser or from a (usually light) VPN client.
Across many operating systems.
VLAN
Virtual Local Area Network.
A group of devices in the same broadcast domain.
Separated logically instead of physically.
NAT
Network Address Translation.
The process where a router or network device translates one IP address into another IP address.
Typically from a private (internal) network IP address to a public IP address and vice versa.
Different types of NAT:
SNAT - Static Network Address Translation
DNAT - Dynamic Network Address Translation
PAT/ NAT Overload - Port Address Translation
- Each host on a LAN is translated to the routers WAN side public IP address joined with a different port number. MOST COMMON.
