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Learn about IP addresses, NAT devices, and router settings to secure your home Wi-Fi network. Explore topics like port forwarding, DMZ, and Dynamic DNS to protect against cyber threats.
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Revising Home Wi-Fi Security Issues Sankardas Roy Department of Computing and Information Sciences Kansas State University
IP addresses in a private network are not globally unique • Private networks use addresses from the following address ranges : • 10.0.0.0 – 10.255.255.255 • 172.16.0.0 – 172.31.255.255 • 192.168.0.0 – 192.168.255.255 • A Private IP network can be connected to the Internet via a NAT device Network Address Translation (NAT) Acknowledgement: http://www.cs.virginia.edu/~itlab/book/slides/index.html
Private Addresses: An Example Scenario Acknowledgement: http://www.cs.virginia.edu/~itlab/book/slides/index.html
Why a Home Router Needs to Work as a NAT Device? • You have multiple computers at home but you have been given only one public IP address by the Internet Service Provider (ISP) • The NAT feature of a home router possibly changes IP addresses (and port numbers) of IP datagrams when the datagrams leave/enter the private network • The NAT feature of a home router allows multiple computers at home to communicate with the outer world.
Basic operation of a NAT Device NAT device has an address translation table (green one); the datagrams (yellow ones) flow in and out. Acknowledgement: http://www.cs.virginia.edu/~itlab/book/slides/index.html
IP masquerading: In this example, the outside world thinks there is only one IP (i.e. 128.143.71.21) inside the private home network. Acknowledgement: http://www.cs.virginia.edu/~itlab/book/slides/index.html
Screenshots of the configuration pages for a few features of the router are shown in the following slides Examples of router features are Firewall Port forwarding IP filtering or MAC filtering DMZ Dynamic DNS Ping blocking A Case Study: the Belkin Wireless Home Router
What We Learned • Open home Wi-Fi poses many threats • Eavesdropping • Web session hijacking • Adversary’s launching attacks using your home network as the launch pad • We discussed the standard solution • Configure your home wireless router with security protocol such as WPA2 • Disable insecure features such as DMZ, WPS, remote access, UPnP, etc.
Questions • What is the difference between Port Forwarding and DMZ? • Can these two features exist together in the same router? • Which option is less dangerous? Why? • What is the Dynamic DNS feature in your home router? • When do we need it? • How does it work?
Reminders • The next class will be in Room 128 • Get credentials to use computers in Room 128 • Please carefully observe your homework grade • KSOL can show some “zeros” by default • I have graded until Homework 4 and posted the grade online • I have also sent you graded Homework 1, 2, 3, 4 via email • You can always email me (sroy@ksu.edu) if any confusion • We can meet off the class • Please attend each class • 30% of the grade comes from the class participation • Ask questions; raise relevant issues in class or via emails