Lecture: Network Address Translation Flashcards
(12 cards)
What is NAT?
NAT (Network Address Translation) is a process that maps private IP addresses to public IP addresses. This is used to allow devices on a private network to communicate with devices on the internet
Why is NAT used?
NAT is primarily used to conserve public IPv4 addresses, as they are limited. It also adds a layer of security by hiding the internal IP addresses of a private network
What are the three types of NAT?
Static NAT
Dynamic NAT
Port Address Translation (PAT) / NAPT
Explain Static NAT.
Static NAT involves a one-to-one mapping between a private IP address and a public IP address. This mapping is fixed and does not change.
Provide an example of a Static NAT configuration.
[R1]interface GigabitEthernet0/0/1
[R1-GigabitEthernet0/0/1]ip address 122.1.2.1 24
[R1-GigabitEthernet0/0/1]nat static global 122.1.2.1 inside 192.168.1.1
[R1-GigabitEthernet0/0/1]nat static global 122.1.2.2 inside 192.168.1.2
[R1-GigabitEthernet0/0/1]nat static global 122.1.2.3 inside 192.168.1.3
Explain Dynamic NAT
Dynamic NAT maps private IP addresses to public IP addresses from a pool of available public IP addresses. The mapping is temporary and assigned when a device initiates communication.
How does Dynamic NAT differ from Static NAT in terms of address utilization?
Dynamic NAT is more efficient in using public IP addresses. It only assigns a public IP address when needed and returns it to the pool when the communication is finished, unlike Static NAT, which maintains a permanent 1:1 mapping.
What are the steps involved in Dynamic NAT?
Step 1: Create a pool of public addresses.
Step 2: Create a standard ACL with private addresses.
Step 3: Bind the ACL to the pool.
Step 4: Identify inside and outside interfaces.
Explain Port Address Translation (PAT) / NAPT.
PAT/NAPT is a type of NAT that translates both IP addresses and port numbers. It allows multiple devices on a private network to share a single public IP address.
How does PAT/NAPT improve public address utilization compared to Dynamic NAT?
PAT/NAPT provides a many-to-one mapping, allowing multiple private IP addresses to share a single public IP address by using different port numbers. Dynamic NAT only provides a one-to-one mapping
What is the configuration command for many-to-single IPv4 PAT?
R2(config)# ip nat inside source list 1 interface serial 0/1/1 overload
What are the verification commands for NAT?
R2# show ip nat translations
R2# show ip nat statistics
