CST3607 Class Notes 2018-12-04

News & Tools

Windows Subsystem for Linux (WSL)

NAT Router Security Solutions: Tips & Tricks You Haven’t Seen Before

GRC’s Link Farm

Trello’s boards, lists, and cards enable you to organize and prioritize your projects in a fun, flexible and rewarding way.

Exam 3 Debriefing

Network Address Translation (NAT)

What does a NAT router do? A NAT router creates a local area network (LAN) of private IP addresses and interconnects that LAN to the wide area network (WAN) known as the Internet. The “Network Address Translation” (NAT) performed by the router allows multiple computers (machines) connected to the LAN behind the router to communicate with the external Internet.1

  • Network Address Translation (NAT) allows many inside IP addresses to be represented by some smaller number of outside/public IP addresses.
    • Static NAT
    • Dynamic NAT
    • Port Address Translation (PAT) a.k.a. Dynamic NAT with Overload

NAT Address Designations

Inside LocalSource host inside address before translation.
Outside LocalAn IP address from which source host is known on the Internet.
This is usually the address of the router interface connected to ISP—the actual Internet address.
Inside GlobalSource host address used after translation to get onto the Internet.
This is also the actual Internet address.
Outside GlobalAddress of outside destination host and, again, the real Internet address.

Lab-09: Chapter 13: Network Address Translation (NAT)

  • Instructions / Errata (pdf)
  • Baseline Simulation (Initial Hardware Setup)
    • (Make sure to rename, by replacing “YourLastName” and adding your First Name)
  • Hands-on Lab 13.1
  • Hands-on Lab 13.2
  • Hands-on Lab 13.3
  • You must be in class to get credit for completing this lab.

For Hands-on Lab 13.3: If you’re unable to remove the GlobalNet NAT pool, because of, %Pool GlobalNet in use, cannot destroy, error, then copy the following commands, in one block, and paste them into the CLI to remove the pool. Otherwise, temporarily disable the interface stop the error.

clear ip nat translation *
config t
no ip nat pool GlobalNet 171.16.10.50 171.16.10.55 netmask 255.255.255.0
no ip nat inside source list 1 pool GlobalNet
end

Read / Do