NAT

Question 1

Port Address Translation (PAT)

Answer 1

• multiple internal hosts can share a single registered IPv4 address

Question 2

NAT Disadvantages

Answer 2

1) Many apps break when the IP NATs
2) End-to-end IP traceability is lost so troubleshooting is harder
3) Complicates tunneling protocols because NATs modify header fields, which interferes with the integrity checks that tunneling protocols use
4) the first packet is process-switched

Question 3

NAT Address Types

Answer 3

1) Inside Global - internal host’s public IP
2) Inside Local - internal host’s private IP
3) Outside Local - outside host’s private IP
4) Outside Global - outside host’s public IP

Question 4

NAT Implementations

Answer 4

1) Static NAT - One-to-One
2) Dynamic NAT - Many-to-Many
3) PAT - Many-to-One

Question 5

NAT Virtual Interface (NVI)

Answer 5

1) No need to identify inside and outside interfaces
2) Classic NAT first performs routing and then translates the address when going from inside to outside, and vice versa in the other direction. NVI performs routing, translation, and then routing again.
3) ip nat enable command in interface mode to use NVI
4) NVI not supported on Cisco IOS XE