NAT, NAT64, NPTv6 Flashcards
What is source NAT?
When the source address is translated to another address as part of the initial translation.
What is Destination NAT?
When the destination address is translated to another address as part of the initial translation.
What is Static NAT?
A hard coded translation of one address to another in the router
What is Dynamic NAT?
When a range of addresses is translated on the fly by the router for a pre-defined pool of available translation addresses.
What are the differences between inside local, inside global, outside local, and outside global addresses?
Inside local: The actual private IP address assigned to a device on the inside network(s).
Inside global: The public IP address that represents one or more inside local IP addresses to the outside.
Outside local: The IP address of an outside host as it appears to the inside network. The IP address does not have to be reachable by the outside but is considered private and must be reachable by the inside network.
Outside global: The public IP address assigned to a host on the outside network. This IP address must be reachable by the outside network.
What is PAT?
Port Address Translation aka NAT overload. When many addresses are translated to a single address. This uses the private address and the port number to map to the global address with a port number in the translation table.
When configuring a destination NAT (from the outside to the inside), what option might you need to add to ensure the router creates a 32 bit entry in the routing table?
add-route
example ip nat outside source tcp 199.10.10.1 80 10.1.1.10 6777 add-route
Command to set an interface to be an inside or outside for NAT?
R1(config-if)# ip nat {inside | outside}
Command to set a static NAT
R1(config)# ip nat {inside | outide} source static {source-address} {dest-address}
Command to create a pool of NAT addresses
R1(config)# ip nat pool NAME {start-address} {end-address*} prefix-length 24
Command to create an ACL to use for NAT
R1(config)# ip access-list standard {network-prefix} {wildcard-mask}
OR
R1(config)# ip access-list extended NAME
R1(config-ext-acl)# permit ip {network-prefix} {wildcard-mask} any
Command to set a pooled NAT
R1(config)# ip nat {inside | outside} source list ACL_NAME pool POOL_NAME
Command to set a dynamic PAT
R1(config)# ip nat inside source list ACL_NAME interface {outside-int} overload
OR
R1(config)# ip nat inside source list ACL_NAME pool POOL_NAME overload
Command to set a static PAT
R1(config)# ip nat {inside | outside} source static tcp {address} {port} {address} {port}
Command to display NAT translations
R1# show ip nat translations [brief]
What is NAT66?
Network Address Translation for IPv6 - Translates IPv6 to IPv6 addresses just like standard NAT for IPv4. This is a stateful protocol meaning that it keeps track of sessions and port numbers.
What is NPTv6?
Network Prefix Translation for IPv6 - Translates IPv6 to IPv6 addresses much like NAT66. However, it only translates prefixes, and it cannot be “overloaded”. It’s a 1:1 translation only. It is also stateless, meaning that it does not track port numbers and sessions which makes it more scalable.
What are the basic commands to set up NPTv6 (NAT66) on a Cisco device? (5 commands)
R1(config)# int {int-id}
R1(config-if)# nat66 inside
R1(config)# int {int-id}
R1(config-if)# nat66 outside
R1(config)# nat66 prefix inside {ipv6-prefix} outside {ipv6-prefix}
What command will verify NPTv6 (NAT66) on a Cisco device?
show nat66 [prefix]
When configuring NTPv6, what is the requirements for the address prefixes?
Both the inside and outside address prefixes must use the same mask (i.e. /64 etc)
What is NAT64 and what are the two types of NAT64?
Network Address Translation of IPv6 to IPv4 addresses. Two types are stateful and stateless?
What are the differences between the two types of NAT64?
Stateful - 1-to-1 translation; does not conserve IPv4 addresses; no bindings created; requires DHCPv6; end-to-end transparency.
Stateless : 1-to-many translation (overload); conserves IPv4 addresses; lacks end-to-end transparency; no requirements on IPv6 address assignments
What are the steps to configure NAT64 on a router?
- enable NAT64 on the IPv6 and the IPv4 interfaces
- create an ipv6 access list to match the traffic to translate
- from global config mode “nat64 prefix stateless {ipv6-prefix}
- from global config mode “nat64 v4 pool NAME {start-ipv4} {end-ipv4}
- from global config mode
