NAT Flashcards
Network Address Translation
RFC ____ reserves certain ranges of IPv4 addresses for private use only
1918
List the three private IPv4 address ranges
10.0.0.0 /8
172.16.0.0 /12
192.168.0.0 /16
T/F: Private addresses cannot be used over the internet
T
T/F: NAT allows all the devices on a single residential LAN to communicate over the internet via the same public IP address
T
NAT is used to modify the ____ and/or ____ of packets
Source and/or destination IP address
T/F: When a response comes back from the broader internet, and the router changes the destination IP address of a packet to match a previously source NAT’d packet, this isn’t destination NAT’ing
T
Static NAT involves mapping _____ to _____
One private IP to one public IP
An inside local IP address is:
The IP address of the host from the perspective of the LAN, AKA the address actually configured on the inside host
An inside global IP address is:
The IP address of the host from the perspective of outside hosts. AKA the address of the inside host AFTER NAT, usually a public IP address
T/F: Static NAT doesn’t really help conserve IP addresses, since it requires a public IP for each private IP anyway
T
What is the command to mark an interface as being connected to the internal network
ip nat inside
What is the command to mark an interface as being connected to the external network
ip nat outside
What is the command to configure a 1-to-1 static NAT mapping
ip nat inside source static {inside-local-ip} {inside-external-ip}
What is the command to view NAT tables saved on the router?
sh ip nat translations
T/F: When using static NAT, port numbers are also changed
F
Port numbers aren’t changed by static NAT
An outside local IP address is:
The ip address of the outside host, from the perspective of the LAN
An outside global IP address is:
The IP address of the outside host, from the perspective of the outside network
T/F: Unless destination NAT is used, outside local and outside global should always remain the same
T
Destination NAT is beyond the CCNA scope
What is the command to clear all dynamic translations in the NAT table?
clear ip nat translation *
T/F: Each time static NAT entries are actually used, dynamic NAT entries are automatically added to the NAT table
T
What is the command to view overview + counter information about NAT on a router
sh ip nat statistics
Which of the following commands will configure a static source NAT mapping of 192.168.10.10 to 203.0.113.10
a) ip nat inside source static 203.0.113.10 192.168.10.10
b) ip nat inside static source 192.168.10.10 203.0.113.10
c) ip nat source inside static 203.0.113.10 192.168.10.10
d) ip nat inside source static 192.168.10.10 203.0.113.10
D