internet address crisis-solution in ipv4

8/2/2019 Internet Address Crisis-Solution in IPV4

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ABSTRACT

I n t e r n e t P r o t o c o l v e r s i o n 4 u s e s a 3 2 b i t I P a d d r e s s . I n t h e o r y , a 3 2 b i t a d d r e s s

s p a c e s h o u l d p r o v i d e a d d r e s s e s f o r m o r e t h a n f o u r b i l l i o n c o m p u t e r s , b u t i n e f f i c i e n c i e s i n a d d r e s s

a l l o c a t i o n m e a n t h a t l e s s t h a n h a l f o f t h e a d d r e s s e s a r e u s e d . T h e r e s u l t i s s o c a l l e d - ' M n t e r n e t a d d r e s s

c r i s i s " - t h e r e ! a r e m o r e c o m p u t e r s t h a n u s a b l e a d d r e s s e s T h e r e f o r e p e r m a n e n t I P a d d r e s s e s h a v e

b e c o m e e x p e n s i v e . T h e r e a r e t w o s o l u t i o n s t o t h e p r o b l e m . O n e i s a l o n g t e r m s o l u t i o n o f u s i n g

I P v 6 , a n d t h e o t h e r i s a s h o r t - t i m e p r a c t i c a l s o l u t i o n c a l l e d N A T w h i c h i s h i g h l y u s e d . T h i s s e m i n a r

t r i e s t o b r i n g o u t t h e [ d e t a i l s o f N A T a n d f i n a l l y h o w i t h e l p s t o i m p l e m e n t t h e I P v 4 t o I P v 6

t r a n s i t i o n s .

N e t w o r k A d d r e s s T r a n s l a t i o n i s a m e t h o d b y w h i c h I P a d d r e s s e s a r e m a p p e d f r o m

o n e r e a l m t o a n o t h e r , i n a n a t t e m p t t o p r o v i d e t r a n s p a r e n t r o u t i n g t o h o s t s . T r a d i t i o n a l l y , N A T

d e v i c e s ) a r e u s e d t o c o n n e c t a n i s o l a t e d a d d r e s s r e a l m w i t h p r i v a t e u n r e g i s t e r e d a d d r e s s e s t o a n

e x t e r n a l r e a l m w i t h g l o b a l l y u n i q u e r e g i s t e r e d a d d r e s s e s .

12.l.INTRODUCTION AND OVERVIEW

T h e n e e d f o r I P A d d r e s s t r a n s l a t i o n a r i s e s w h e n a n e t w o r k ' s i n t e r n a l I P a d d r e s s e s

c a n n o t b e u s e d o u t s i d e t h e n e t w o r k e i t h e r b e c a u s e t h e y a r e i n v a l i d f o r u s e o u t s i d e , o r b e c a u s e t h e

i n t e r n a l a d d r e s s i n g m u s t b e k e p t p r i v a t e f r o m t h e e x t e r n a l n e t w o r k .

A d d r e s s t r a n s l a t i o n a l l o w s h o s t s i n a p r i v a t e n e t w o r k t o t r a n s p a r e n t l y c o m m u n i c a t e

w i t h d e s t i n a t i o n s o n a n e x t e r n a l n e t w o r k a n d v ic e v e r s a . T h e r e a r e a v a r i e t y o f f l a v o r s o f N A T a n d

t e r m s t o m a t c h t h e m . T h i s d o c u m e n t a t t e m p t s t o d e f i n e t h e t e r m i n o l o g y u s e d a n d t o i d e n t i f y v a r i o u s

f l a v o r s o f N A T . T h e d o c u m e n t a l s o a t t e m p t s t o d e s c r i b e o t h e r c o n s i d e r a t i o n s a p p l i c a b l e t o N A T

d e v i c e s i n g e n e r a l .

N A T d e v i c e s a t t e m p t t o p r o v i d e a t r a n s p a r e n t r o u t i n g s o l u t i o n t o t h e e n d h o s t s t r y i n g

t o c o m m u n i c a t e f r o m d i s p a r a t e a d d r e s s r e a l m s . T h i s i s a c h i e v e d b y m o d i f y i n g e n d n o d e a d d r e s s e s e n -

r o u t e a n d m a i n t a i n i n g s t a t e f o r t h e s e u p d a t e s s o t h a t d a t a g r a m s p e r t a i n i n g t o a s e s s i o n a r e r o u t e d t o h e

r i g h t - e n d n o d e i n e i t h e r r e a l m . T h i s s o l u t i o n o n l y w o r k s w h e n t h e a p p l i c a t i o n s d o n o t u s e t h e I P

a d d r e s s e s a s p a r t o f t h e p r o t o c o l i t s e l f . F o r e g : i d e n t i f y i n g e n d p o i n t s u s i n g D N S n a m e s r a t h e r t h a n

a d d r e s s e s m a k e s a p p l i c a t i o n s l e s s d e p e n d e n t o f t h e a c t u a l a d d r e s s e s t h a t N A T c h o o s e s a n d a v o i d s t h e

n e e d t o a l s o t r a n s l a t e p a y l o a d c o n t e n t s w h e n N A T c h a n g e s a n I P a d d r e s s .

T h e N A T f u n c t i o n c a n n o t b y i t s e l f s u p p o r t a l l a p p l i c a t i o n s t r a n s p a r e n t l y a n d


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Internet Address Crisis-Solutions in 1PV4

2.WHAT IS NAT?

Short for Network Address Translation, an Internet standard that enables a local-area network

(LAN) to use one set of IP addresses for internal traffic and a second set of addresses for external traffic. A NAT

box located where the LAN meets the Internet makes all necessary IP address translations. In computer

networking, the process of network address translation (NAT, also known as network masquerading or IP-

masquerading) involves re-writing the source and/or destination addresses of IP packets as they pass through a

router or firewall. Most systems using NAT do so in order to enable multiple hosts on a private network to

access the Internet using a single public IP address (see gateway). According to specifications, routers should

not act in this way. but many network administrators find NAT a convenient technique and use it widely.

Nonetheless, NAT can introduce complications in communication between hosts.

The NAT router translates traffic coming into and leaving the private network.

Network Address Translation allows a single device, such as a router, to act as an agent between the Internet

(or "public network") and a local (or "private") network. This means that only a single, unique IP address is

required to represent an entire group of computers


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V i?:in.i.jfoi lii

W e h a v e a s m a l l E t h e r n e t n e t w o r k u s i n g o n e o f t h e r e s e r v e d n e t w o r k a d d r e s s e s . T h e n e t w o r k h a s a

m a s q u e r a d e r o u t e r p r o v i d i n g a c c e s s t o t h e I n t e r n e t . O n e o f t h e w o r k s t a t i o n s o n t h e j | n e t w o r k ( 1 9 2 . 1 6 8 . 1 . 3 ) w i s h e s t oe s t a b l i s h a c o n n e c t i o n t o t h e r e m o t e h o s t 2 0 9 . 1 . 1 0 6 . 1 7 8 o n p o r t 8 8 8 8 T h e w o r k s t a t i o n r o u t e s i t s d a t a g r a m t o t h e

m a s q u e r a d e r o u t e r , w h i c h i d e n t i f i e s t h i s c o n n e c t i o n r e q u e s t | a s r e q u i r i n g m a s q u e r a d e s e r v i c e s . I t a c c e p t s t h e d a t a g r a m

a n d a l l o c a t e s a p o r t n u m b e r t o u s e ( 1 0 3 5 ) s u b s t i t u t e s i t s o w n I P a d d r e s s a n d p o r t n u m b e r f o r t h o s e o f t h e o r i g i n a t i n g

h o s t , a n d t r a n s m i t s t h e d a t a g r a m t o t h e d e s t i n a t i o n h o s t . T h e d e s t i n a t i o n h o s t b e l i e v e s i t h a s r e c e i v e d a c o n n e c t i o n

r e q u e s t f r o m t h e m a s q u e r a d e h o s t a n d g e n e r a t e s a r e p l y d a t a g r a m . T h e m a s q u e r a d e h o s t , u p o n r e c e i v i n g t h i s d a t a g r a m ,

f i n d s t h e a s s o c i a t i o n i n i t s m a s q u e r a d e t a b l e a n d r e v e r s e s t h e s u b s t i t u t i o n i t p e r f o r m e d o n t h e o u t g o i n g d a t a g r a m . I t

t h e n t r a n s m i t s t h e r e p l y d a t a g r a m t o t h e o r i g i n a t i n g h o s t .

T h e l o c a l h o s t b e l i e v e s i t i s s p e a k i n g d i r e c t l y t o t h e r e m o t e h o s t . T h e r e m o t e h o s t k n o w s n o t h i n g a b o u t I h e l o c a l h o s t a t

a l l a n d b e l i e v e s i t h a s r e c e i v e d a c o n n e c t i o n f r o m t h e m a s q u e r a d e h o s t . T h e m a s q u e r a d e h o s t k n o w s t h e s e t w o h o s t s a r e

s p e a k i n g t o e a c h o t h e r , a n d o n w h a t p o r t s , a n d p e r f o r m s [ h e a d d r e s s a n d p o r t t r a n s l a t i o n s n e c e s s a r y t o a l l o w

c o m m u n i c a t i o n .

4. FORMS OF NAT

NAT has many forms and can work in several ways:

Static NAT - A type of NAT in which a private IP address is mapped to a public IP address, where the

public address is always the same IP address (i.e., it has a static address). This allows an internal host,

such as a Web server, to have an unregistered (private) IP address and still be reachable over the

Internet.


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Overloading - A form of dynamic NAT that maps multiple unregistered IP addresses to a single registered

IP address by using different ports. This is known also as PAT (Port Address Translation), single

address NAT or port-level multiplexed NAT.

Dynamic NAT - A type of NAT in which a private IP address is mapped to a public IP address drawing from

a pool of registered (public) IP addresses. Typically, the NAT router in a network will keep a table of

registered IP addresses, and when a private IP address requests access to the Internet, the router chooses an IP

address from the table that is not at the time being used by another private IP address. Dynamic NAT helps to

secure a network as it masks the internal configuration of a private network and makes it difficult for someone

outside the network to monitor individual usage patterns. Another advantage of dynamic NAT is that it allows

a private network to use private IP addresses that are invalid on the Internet but useful as internal addresses

Overlapping - When the IP addresses used on your internal network are registered IP addresses in use on

In overloading, each computer on the private network is translated to the same IP address

(213.18.123.100), but with a different port number assignment.

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another network, the router must maintain a lookup table of these addresses so that it can intercept them

and replace them with registered unique IP addresses. It is important to note that the NAT router must

translate the "internal" addresses to registered unique addresses as well as translate the "external"

registered addresses to addresses that are unique to the private network. This can be done either through

static NAT or by using DNS and implementing dynamic NAT.


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I n t e r n e t A d d r e s s C r i s i s - S o l u t i o n i n IPV4

5.BASIC NAT VS PORT NUMBER TRANSLATION

T w o k i n d s o f n e t w o r k a d d r e s s t r a n s l a t i o n e x i s t . T h e t y p e o f t e n p o p ul a r l y c a l l e d s i m p l y " N A T "

( a l s o s o m e t i m e s n a m e d " N e t w o r k A d d r e s s P o r t T r a n s l a t i o n " o r " N A P T " ) r e f e r s t o n e t w o r k a d d r e s s t r a n s l a t i o n

i n v o l v i n g t h e m a p p i n g o f p o r t n u m b e r s , a l l o w i n g m u l t i p l e m a c h i n e s t o s h a r e a s i n g l e I P a d d r e s s . T h e o t h e r ,

t e c h n i c a l l y s i m p l e r , f o r m - a l s o c a l l e d N A T o r " o n e - t o - o ne N A T " o r " b a s i c N A T " o r " s t a t i c N A T " - i n v o l v e s o n l y

a d d r e s s t r a n s l a t i o n , n o t p o r t m a p p i n g . T h i s r e q u i r e s a n e x t e r n a l I P a d d r e s s f o r e a c h s i m u l t a n e o u s c o n n e c t i o n .

B r o a d b a n d r o u t e r s o f t e n u s e t h i s f e a t u r e , s o m e t i m e s l a b e l e d " D M Z h o s t " , t o a l l o w a d e s i g n a t e d c o m p u t e r t o a c c e p t

a l l e x t e r n a l c o n n e c t i o n s e v e n w h e n T h e r o u t e r i t s e l f u s e s t h e o n l y a v a i l a b l e e x t e r n a l I P a d d r e s s .

N A T w i t h p o r t - t r a n s l a t i o n c o m e s i n t w o s u b - t y p e s : s o u r c e a d d r e s s t r a n s l a t i o n ( s o u r c e N A T ) , w h i c h r e w r i t e s t h e I P

a d d r e s s o f t h e c o m p u t e r w h i c h i n i t i a t e d t h e c o n n e c t i o n ; a n d i t s c o u n t e r p a r t , d e s t i n a t i o n a d d r e s s t r a n s l a t i o n

( d e s t i n a t i o n N A T ) . I n p r a c t i c e , b o t h a r e u s u a l l y u s e d t o g e t h e r i n c o o r d i n a t i o n f o r t w o - w a y c o m m u n i c a t i o n .

6.CLASSIFICATIONS OF NAT

Different types of NAT:-

A p p l i c a t i o n s t h a t d e a l w i th N A T s o m e t i m e s n e e d t o c h a r a c t e r i z e N A T b y t y p e . T h e S T U N p r o t o c o l , [ 1 ]

p r o p o s e d t o c h a r a c t e r i z e N e t w o r k a d d r e s s t r a n s l a t i o n a s F u l l c o n e N A T , r e s t r i c t e d c o n e N A T , p o r t r e s t r i c t e d c o n e

N A T o r s y m m e t r i c N A T . [2 ] N o t e t h a t i t i s i n d e e d c a l l e d " c o n e " a n d n o t p o s s i b l y a t y p e o f " c l o n e " .

W i t h f u l l c o n e N A T , a l s o k n o w n a s o n e - t o - o n e N A T , a l l r e q u e s t s f r o m t h e s a m e i n t e r n a l I P a d d r e s s a n d p o r ta r e m a p p e d t o t h e s a m e e x t e r n a l I P a d d r e s s a n d p o r t . A n e x t e r n a l h o s t c a n s e n d a p a c k e t t o t h e i n t e r n a l h o s t ,

b y s e n d i n g a p a c k e t t o t h e m a p p e d e x t e r n a l a d d r e s s .

W i t h r e s t r i c t e d c o n e N A T , a l l r e q u e s t s f r o m t h e s a m e i n t e r n a l I P a d d r e s s a n d p o r t a r e m a p p e d t o t h e s a m ee x t e r n a l I P a d d r e s s a n d p o r t . U n l i k e a f u l l c o n e N A T , a n e x t e r n a l h o s t c a n s e n d a p a c k e t t o t h e i n t e r n a l h o s t

o n l y i f t h e i n t e r n a l h o s t h a d p r e v i o u s l y s e n t a p a c k e t t o i t .

W i t h P o r t r e s t r i c t e d c o n e N A T o r s y m m e t r i c N A T i s l i k e a r e s t r i c t e d c o n e N A T , b u t t h e r e s t r i c t i o n i n c l u d e sp o r t n u m b e r s . S p e c i f i c a l l y , a n e x t e r n a l h o s t c a n s e n d a p a c k e t t o a p a r t i c u l a r p o r t o n t h e i n t e r n a l h o s t o n l y

i f t h e i n t e r n a l h o s t h a d p r e v i o u s l y s e n t a p a c k e t f r o m t h a t p o r t t o t h e e x t e r n a l h o s t .

W i t h s y m m e t r i c N A T a l l r e q u e s t s f r o m t h e s a m e i n t e r n a l I P a d d r e s s a n d p o r t t o a s p e c i f i c d e s t i n a t i o n I Pa d d r e s s a n d p o r t a r e m a p p e d t o a u n i q u e e x t e r n a l s o u r c e I P a d d r e s s a n d p o r t . I t t h e s a m e i n t e r n a l h o s t s e n d s

k i h h d d d d i f f d i i d i f f i i d O l


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2 . T o t h e e x t e n t t h a t N A T d e p e n d s o n a m a c h i n e o n t h e l o c a l n e t w o r k t o i n i t i a t e a n y c o n n e c t i o n t o h o s t s o n t h eo t h e r s i d e o f t h e r o u t e r , i t p r e v e n t s m a l i c i o u s a c t i v i t y i n i t i a t e d b y o u t s i d e h o s t s f r o m r e a c h i n g t h o s e l o c a l

h o s t s . T h i s c a n e n h a n c e t h e r e l i a b i l i t y o f l o c a l s y s t e m s b y s t o p p i n g w o r m s a n d e n h a n c e p r i v a c y b y

d i s c o u r a g i n g s c a n s . M a n y N A T - e n a b l e d f i r e w a l l s u s e t h i s a s t h e c o r e o f t h e p r o t e c t i o n t h e y p r o v i d e .

3 . T h e g r e a t e s t b e n e f i t o f N A T i s t h a t i t i s a p r a c t i c a l s o l u t i o n t o t h e i m p e n d i n g e x h a u s t i o n o ( I P v 4 a d d r e s ss p a c e .

4 . N e t w o r k s t h a t p r e v i o u s l y r e q u i re d a C l a s s B I P r a n g e o r a b l o c k o f C l a s s C n e t w o r k a d d r e s s e s c a n n o w b ec o n n e c t e d t o t h e I n t e r n e t w i t h a s l i t t l e a s a s i n g l e I P a d d r e s s ( m a n y h o m e n e t w o r k s a r e s e t u p t h i s w a y ) .

5 . T h e m o r e c o m m o n a r r a n g e m e n t i s h a v i n g m a c h i n e s t h a t r e q u i r e t r u e b i d i r e c t i o n a l a n d u n f e t t e r e dc o n n e c t i v i t y s u p p l ie d w i t h a ' r e a l ' I P a d d r e s s e s , w h i l e h a v i n g m a c h i n e s t h a t d o n o t p r o v i d e s e r v i c e s t o

o u t s i d e u s e r s ( e . g , a s e c r e t a r y ' s c o m p u t e r ) t u c k e d a w a y b e h i n d N A T w i t h o n l y a f e w I P a d d r e s s e s u s e d t o

e n a b l e I n t e r n e t a c c e s s .

8. DRAWBACKS

1 . H o s t s b e h i n d a N A T - e n a b l e d r o u t e r d o n o t h a v e t r u e e n d - t o - e n d c o n n e c t i v i t y a n d c a n n o t p a r t i c i p a t e i ns o m e I n t e r n e t p r o t o c o l s .

2. S e r v i c e s t h a t r e q u i r e t h e i n i t i a t i o n o f T C P c o n n e c t i o n s f r o m t h e o u t s i d e n e t w o r k , o r s t a t e l e s s p r o t o c o l s

s u c h a s t h o s e u s i n g U D P , c a n b e d i s r u p t e d . U n l e s s t h e N A T r o u t e r m a k e s a s p e c i f i c e f f o r t t o s u p p o r t s u c h

p r o t o c o l s , i n c o m i n g p a c k e t s c a n n o t r e a c h t h e i r d e s t i n a t i o n .

3 . S o m e p r o t o c o l s c a n a c c o m m o d a t e o n e i n s t a n c e o f N A T b e t w e e n p a r t i c i p a t i n g h o s t s ( " pa s s i v e m o d e " F T P ,f o r e x a m p l e ) , s o m e t i m e s w i t h t h e a s s i s t a n c e o f a n A p p l i c a t i o n L a y e r G a t e w a y , b u t f a i l w h e n b o t h s y s t e m s

a r e s e p a r a t e d f r o m t h e I n t e r n e t b y N A T .

4 . U s e o f N A T a l s o c o m p l i c a t e s s e c u r i t y p r o t o c o l s s u c h a s I P s e c5 . D e p e n d i n g o n o n e ' s p o i n t o f v i e w , a n o t h e r d r a w b a c k o f N A T i s t h a t i t g r e a t l y s l o w e d t h e a c c e p t a n c e o f

I P v 6 , r e l e g a t i n g i t t o r e s e a r c h n e t w o r k s a n d l i m i t e d p u b l i c u s e .

( E n d - t o - e n d c o n n e c t i v i t y h a s b e e n a c o r e p r i n c i p l e o f t h e I n t e r n e t , s u p p o r t e d f o r e x a m p l e b y t h e I n t e r n e t

A r c h i t e c t u r e b o a r d . S o m e p e o p l e t h u s r e g a r d N A T a s a d e t r i m e n t t o t h e P u b l i c I n t e r n e t . S o m e i n t e r n e t s e r v i c e

p r o v i d e r s ( I S P s ) o n l y p r o v i d e t h e i r c u s t o m e r s w i t h " l o c a l " I P a d d r e s s e s . T h u s , t h e s e c u s t o m e r s m u s t a c c e s s

s e r v i c e s e x t e r n a l t o t h e I S P ' s n e t w o r k t h r o u g h N A T . A s a r e s u l t , s o m e m a y a r g u e t h a t s u c h c o m p a n i e s d o n o t

p r o p e r l y p r o v i d e " I n t e r n e t " s e r v i c e . ) j 9.APPLICATIONS AFFECTED BY NATSome higher-layer protocols (such as FTP and SIP) send network layer address information

i id li ti l d FTP i ti d f l t ti f t l t ffi


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obviously need to understand the higher-layer protocol that they need to fix, and so each protocol with this

problem requires a separate ALG.

Another possible solution to this problem is to use NAT traversal techniques using protocols

such as STUN or ICE or proprietary approaches in a session border controller. NAT traversal is possible in

both TCP- and UDP-based applications, but the UDP-based technique is simpler, more widely understood,

and more compatible with legacy NATs. In either case, the high level protocol must be designed with NAT

traversal in mind, and it does not work reliably across symmetric NATs or other poorly-behaved legacy

NATs.

Yet another possibility is UPnP (Universal Plug and Play) or Bonjour but this requires the

cooperation of the NAT device.

Most traditional client-server protocols (FTP being the main exception), however, do not send

layer 3 contact information and therefore do not require any special treatment by NATs. In fact, avoiding

NAT complications is practically a requirement when designing new higher-layer protocols today.

N A T s c a n a l s o c a u s e p r o b l e m s w h e r e I P s e c e n c r y p t i o n i s a p p l i e d a n d i n c a s e s w h e r e m u l t i p l e d e v i c e s

s u c h a s S I P p h o n e s a r e l o c a t e d b e h i n d a N A T . P h o n e s w h i c h e n c r y p t t h e i r s i g n a l l i n g w i t h I P s e c e n c a p s u l a t e t h e p o r t

i n f o r m a t i o n w i t h i n t h e I P s e c p a c k e t m e a n i n g t h a t N A ( P ) T d e v i c e s c a n n o t a c c e s s a n d t r a n s l a t e t h e p o r t . I n t h e s e

c a s e s t h e N A ( P ) T d e v i c e s r e v e r t t o s i m p l e N A T o p e r a t i o n . T h i s m e a n s t h a t a l l t r a f f i c r e t u r n i n g t o t h e N A T w i l l b e

m a p p e d o n t o o n e c l i e n t c a u s i n g t h e s e r v i c e t o f a i l . T h e r e a r e a c o u p l e o f s o l u t i o n s t o t h i s p r o b l e m , o n e i s t o u s e T L S

w h i c h o p e r a t e s a t l e v e l 4 i n t h e O S I R e f e r e n c e M o d e l a n d t h e r e f o r e d o e s n o t m a s k t h e p o r t n u m b e r , o r t o

E n c a p s u l a t e t h e I P s e c w i t h i n U D P - t h e l a t t e r b e i n g t h e s o l u t i o n c h o s e n b y T I S P A N t o a c h i e v e s e c u r e N A T

t r a v e r s a l .

I 10.IPv6 - is it creeping into your network?

!

j

M o s t o r g a n i z a t i o n s a r e c u r r e n t l y r u n n i n g v e r s i o n 4 o f t h e I n t e r n e t p r o t o c o l ( I P ) o n t h e i r n e t w o r k s .

S u p p l i e r s h a v e f o r s o m e t i m e b e e n p r o v i d i n g e q u i p m e n t t o a n e w , h i g h e r s t a n d a r d k n o w n a s I P V 6 a n d n e t w o r k s a r e

m i g r a t i n g .

I P v 6 ( I n t e r n e t P r o t o c o l v e r s i o n 6 ) i s t h e n e x t g e n e r a t i o n o f t h e p r o t o c o l t h a t r u n s t h e I n t e r n e t . C u r r e n t l y a

s e t o f d r a f t s t a n d a r d s i n t h e I n t e r n e t E n g i n e e r i n g T a s k F o r c e ( I E T F ) , i t i s d e s i g n e d t o i m p r o v e u p o n I P v 4 , i n t e r m s

o f s c a l a b i l i t y , e a s e - o f - c o n f i g u r a t i o n , s e c u r i t y a n d t o r e - i n t r o d u c e t h e o r i g i n a l T C P / I P b e n e f i t s f o r g l o b a l


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E a s i e r a d d r e s s m a n a g e m e n t a n d d e l e g a t i o n E a s y a d d r e s s a u t o c o n f i g u r a t i on E m b e d d e d I P s e c ( e n c r y p t e d s e c u r i t y ) D u p l i c a t e A d d r e s s D e t e c t i o n ( D A D ) f e a t u r e .

11. COMPARISON OF IPv4 VERSUS IPv6

IPv4 Solution IPv6 Solution

IP ServiceAddressing Range 32-bit, Network Address Translation 128-bit, Multiple Scopes

Serverless, Reconfiguration, DHCP

Autoconfiguration DHCP

Security IPSec IPSec Mandated, works End-to-End

Mobility Mobile IP Mobile IP with Direct Routing

Quality-of-Service Differentiated Service, Integrated Service Differentiated Service, Integrated Service

IP Multicast _ ..........................IGMP/PIM/Multicast BGP

MLD/PIM/MulticastBGP, Scope Identifier

....................... _ J _

12 .CONCLUSION

N A T h a s b e e n a g o o d r e s p o n s e i n a n y w a y s t o t h e p r o b l e m o f l i m i t e d I P v 4 a d d r e s s s p a c e , b u t i t h a s a l s o

c a u s e d m a n y p r o b l e m s . D e v i c e s i n p r i v a t e n e t w o r k s c a n n o t a c t a s s e r v e r s o r p a r t i c i p a t e i n P 2 P a p p l i c a t i o n s w h e n

N A T c h a n g e s p a c k e t s . N A T h a s a l s o s e r v e d t o u n d e r m i n e t h e s e c u r i t y p r o v i s i o n s t h a t h a v e b e e n c r e a t e d t o p r o t e c t

t h e u s e r s o f t h e I n t e r n e t . T h e c o m b i n e d u s e o f N A T a n d I P s e c n e t w o r k l e v e l s e c u r i t y o u t r i g h t p r e v e n t s s u c c e s s f u l

c o m m u n i c a t i o n b e t w e e n d e v i c e s u n d e r I P v 4 . S e c u r e c o m m u n i c a t i o n h a s p r o v e n t o b e a n e c e s s i t y i n a w o r l d t h a t h a s

d e m o n s t r a t e d r e m a r k a bl e m a l f e a s a n c e .


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S N G C E , K o l e n c h e r yD e p t o f C S E

13 BIBLIOGRAPHY AND WEBLIOGRAPHY

BOOKS , *

1.ANDREW .S .TANENBAUM

"Computer Networks"

CONTENTS

1 . I N T R O D U C T I O N A N D O V E R V I E W 12 . W H A T I S N A T ? 33 . N A T O P E R A T I O N S 44 . F O R M S O F N A T 55 . B A S I C N A T V S P O R T N U M B E R T R A N S L A T I O N 86 . C L A S S I F I C A T I O N S O F N A T 97 . B E N E F I T S 1 08 . D R A W B A C K S I I9 . A P P L I C A T I O N S A F F E C T E D B Y N A T 1 210 . I P V 6 - I S I T C R E E P I N G I N T O N E T W O R K 1 4 1 1 . C O M P A R I S O N O F I P V 4 V E R S U S I P V 6 1 513 . C O N C L U S I O N 1 6

B I B L I O G R A P H Y A N D W E B L I O G R A P H Y 17
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internet address crisis-solution in ipv4

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