chp 9 nat Flashcards
1
Q
ipv4 private address space
A
- not enough ip addresses
- private addresses are used within organizations
- not routed on internet
- must be translated by nat
2
Q
network address translation (nat)
A
- to conserve public ipv4 addresses
- implemented at border network devices
- private addresses are translated to public addresses
- internal address is hidden
3
Q
static nat
A
- one to one mapping of local and global addresses
- configured by network admin and remain constant
- useful when internal servers must be accessible from the outside network
4
Q
dynamic nat
A
- uses pool of public addresses
- assigns them on first come first serve basis
- requires enough public addresses to satisfy all simultaneous users
5
Q
port address translation (pat)
A
- maps multiple private ip addresses to public ip addresses
- uses the pair source port and source ip address to keep track of what traffic belongs to each client
- aka nat overload
- validates that incoming packets were requested, added security
6
Q
benefits of nat
A
- conserves ip addresses
- increases the flexibility of connections to the public network
- provides consistency for internal network addressing schemes
- provides network security
7
Q
disadvantages of nat
A
- worse performance
- end to end addressing is lost
- end to end traceability is lost
- initiating tcp connections can be interrupted
8
Q
port forwarding
A
- forwarding a network port from one network node to another
- a packet sent to a public ip and port of a router can be forwarded to a private ip and port inside the network
- useful when server with private ip needs to be reached from outside network