Day 8 - NAT Flashcards
NAT is defined in RFC _____
3022
NATs key use is to conserve __________ by allowing networks to use __________ IPv4 addresses
IPv4 addresses
private
NAT translates nonroutable, __________ and _________ addresses into routable ___________ addresses
Private
Internal
Public
In NAT terminology, the __________ __________ is the set of networks that are subject to translation
Inside network
Solve for the definition for NAT addresses:
Most likely a private address used by a PC either statically or dynamically within the boundaries of a local network
Inside local address
Solve for the definition for NAT addresses:
A valid public address that the inside host is given when it exits the NAT router
Inside global address
Solve for the definition for NAT addresses:
A reachable IPv4 address assigned to a host on the internet
Outside global address
Solve for the definition of the type of NAT:
Permanent One-to-One mapping usually between a public and private IP Address
Static NAT
Solve for the definition of the type of NAT:
Uses a pool of addresses which are handed out on an as needed, first come first served basis.
Usually for internal hosts which connect to the internet but do not accept incoming traffic and addresses
Dynamic NAT
Solve for the definition of the type of NAT:
Allows the same public IP Address to be reused by multiple internal hosts
PAT (Port Address Translation)
What is another term for Port Address Translation (PAT)?
NAT Overload
Other than the IP address what is also tracked when using PAT?
Port numbers
NAT overload attempts to preserve the original __________ ___________
Source port
What 3 port groups can NAT Overload assign to?
0-511
512-1023
1024-65535
What are these considered below, concerning NAT
Performance is degraded
End-to-End functionality is degraded
End-to-End IP traceability is lost
Tunneling is more complicated
Services can be disrupted
These are all limitations of NAT
Based on the topology, configure static NAT mapping the local server to an global IP of 209.165.200.254
R1
ip nat inside source static 192.168.10.254 209.165.200.254
interface serial0/0/0
ip nat inside
interface serial0/1/0
ip nat outside
Based on the topology, configure dynamic NAT for a pool called NAT-POOL1 that is ranging from IP address 209.165.200.226 - 209.165.200.240 with 32 available addresses
Be sure and permit the internal network to be able to be NAT’d
R1
ip nat pool NAT-POOL1 209.165.200.226 209.165.200.240 netmask 255.255.255.224
access-list 1 permit 192.168.0.0 0.0.255.255
ip nat inside source list 1 pool NAT-POOL1
int serial 0/0/0
ip nat inside
int serial 0/1/0
ip nat outside
Based on the topology, configure NAT to overload serial interface 0/0/0 that permits the 192.168.X.X network to be able to be NAT’d
R1
access-list 1 permit 192.168.0.0 0.0.255.255
ip nat inside source list 1 int serial 0/1/0 overload
int s0/0/0
ip nat inside
int serial 0/1/0
ip nat outside
Based on the topology, configure dynamic NAT for a pool called NAT-POOL1 that is ranging from IP address 209.165.200.226 - 209.165.200.240 with 32 available addresses. Make sure to overload this pool
Be sure and permit the internal network to be able to be NAT’d
R1
ip nat pool NAT-POOL1 209.165.200.226 209.165.200.240 netmask 255.255.255.224
access-list 1 permit 192.168.0.0 0.0.255.255
ip nat inside source list 1 pool NAT-POOL1 overload
int serial 0/0/0
ip nat inside
int serial 0/1/0
ip nat outside
What command would you use to verify current NAT translations?
show ip nat translations
What verification command would show information about the total number of active translations, configuration parameters, number of addresses in the pool, etc.
show ip nat statistics
What command would you use to clear dynamic NAT entries
clear ip nat translation *
What command would you use to verify the operation of the NAT feature by displaying information about every packet that the router translates?
debug ip nat
When viewing show ip nat translation what does Inside Local Address mean?
The IP Address actually configured on the inside host’s operating system
When viewing show ip nat translation what does Inside Global Address mean?
The NAT’d address of the inside host as it will be reached by the outside network
When viewing show ip nat translation what does Outside Local Address mean?
The IP Address of the outside host as it appears to the inside network
Context: A server off of your internal network that you’re trying to reach. This is the IP Address that the internal network will use to try and reach it on the outside.
When viewing show ip nat translation what does Outside Global Address mean?
The IP Address assigned to the host on the outside network by the external host’s owner
Context: This is the actual assigned IP Address by the external host’s owner.
Most times the Outside Global Address and the Outside Local Address will be the same
