NAT Flashcards
Port Address Translation (PAT)
- multiple internal hosts can share a single registered IPv4 address
NAT Disadvantages
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
NAT Address Types
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
NAT Implementations
1) Static NAT - One-to-One
2) Dynamic NAT - Many-to-Many
3) PAT - Many-to-One
NAT Virtual Interface (NVI)
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