4
1. , IP- 5
2. , ..7
3. IP-.10
, -, , IP-. , . , IP-.
. .
1, 2, 3, 4, 4 . , 1=2=3=4=0,
Y1 = 10*X4 + 3
Y2 = Y1 + X3
Y3 = Y1 + X2
Y4 = Y1 + X1
Y1, Y2, Y3 Y4 .
, IP-
. . , , .
. 0,1,2,3,4,5,6,7,8,9. ( ) 100, 101 .. , 3567 3 *103 + 5 *102 + 6 *101 + 7 *100 = 3567.
( ). 0 1. ( ) 20, 21 .. , 3567 1 *211 + 1 *210 + 0 *29 + 1 *28 + 1 *27 + 1 *26 + 1 *25 + 0 *24+ 1 *23 + 1 *22 + 1 *21 + 1 *20 = 11101111011112 = 2048 + 1024 + 256 + 128 + 64 + 32 + 8 + 4 + 2 + 1 = 3567.
IP- . 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F. , . 1.
.1
A | ||
B | ||
C | ||
D | ||
E | ||
F |
|
|
( ) 160, 161 .. , 3567 13 *162 + 14 *161 + 15 *160 = D *162 + E *161 + F *160 = 0xDEF = 0def, 0 . .
IP- IP-, 32 (). 4 8 , . IP- - . , Y1=73, Y2=58, Y3=85 Y4=167. - IP- Y1.Y2.Y3.Y4 .2.
.2
- IP- | 73. 58. 85. 167 |
IP- | 01001001. 00111010. 01010101. 10100111 |
IP- | 49. 3. 55. 7 |
1.
.2 IP- Y1.Y2.Y3.Y4.
IP- M n, W = mod n M M/n. , Y1=73, Y2=58, Y3=85, Y4=167, M= Y1Y2Y3Y4=735885167, n=5. W=mod n M = mod5735885167. W .
1. w1 = M/n = 735885167/5 = 147177033.4;
2. w2 = INT(w1) = 147177033;
3. w3 = n*w2 = 735885165;
4. W= W=mod5735885167= M w3 = 2.
2.
mod 19 Y1Y2Y3Y4.
IP- Ȕ . Ȕ: 0+0=0, 0+1=0, 1+0=0, 1+1=1. , Ȕ Y1=73, Y2=58
Y1è 010010012
Y2è 001110102
--------------------
000010002 è 8
3.
Y1 Y2, Ȕ.
,
. 1.
(Proxy) , Int-1, Int-2 Int-3 ;
;
DHCP ,
AAA , ,
-mail ,
DB1 DB2 .
|
: , .
. proxy- . : (Name User ID) (Password), -. Password Authentication Protocol (PAP) Challenge Handshake Authentication Protocol (CHAP), PPP.
|
|
PAP . , PAP .
CHAP proxy- V, W, (Name) (Password). , W=f(V, Name, Password). , V, Name W, f. W , () V Password. . - (digest function) -, . MD5 [RFC 1321, PS]. Proxy- - W, Name Challenge=V. AAA proxy- V Name Password W proxy-. Proxy- W, -: , .
proxy- , .. DB1 DB2 , DB1 DB2 ( /) .
.
. 2 : (Name) Ivanov, (Password = K1m), (V) 123456. . Password.
.
proxy- (code=01) CHAP (Protocol = 0xc223) V = 123456 = 0x1E240. .
1. , ASCII (. 3).
. 3
(0) 000 | (1) 001 | (2) 010 | (3) 011 | (4) 100 | (5) 101 | (6)110 | (7) 111 | |
(0) 0000 | NUL | DLE | SP | @ | P | ' | p | |
(1) 0001 | SOH | DC1 | ! | A | Q | a | q | |
(2) 0010 | STX | DC2 | B | R | b | r | ||
(3) 0011 | ETX | DC3 | # | C | S | c | s | |
(4) 0100 | EOT | DC4 | $ | D | T | d | t | |
(5) 0101 | ENQ | NAK | % | E | U | e | u | |
(6) 0110 | ACK | SYN | & | F | V | f | v | |
(7) 0111 | BEL | ETB | ' | G | W | g | w | |
(8) 1000 | BS | CAN | ( | H | X | h | x | |
(9) 1001 | HT | EM | ) | I | Y | i | y | |
(a) 1010 | LF | SUB | * | : | J | Z | j | z |
(b) 1011 | VT | ESC | + | ; | K | [ | k | { |
(c) 1100 | FF | IS4 | , | < | L | \ | l | | |
(d) 1101 | CR | IS3 | - | = | M | ] | m | } |
(e) 1110 | SO | IS2 | . | > | N | ^ | n | ~ |
(f) 1111 | S1 | IS1 | / | ? | O | _ | o | DEL |
|
|
, . .3 Ivanov 0x4976616e6f76, K1m 04b316d.
2. 0 4b316d 0 01e240, F=0x 4 0 b 1 3 e 1 2 6 4 d 0.
3. W = mod Password F = mod04b316d 40b13e1264d0 = mod 4927853 71129994781904 = 4493476 = 0x448cbc.
Name=0x4976616e6f76 W = 0x448cbc.
proxy- W -, Name V.
proxy- - W, Name=0x4976616e6f76 V=0x1E240.
proxy- (code=03) .
4.
.2 :
(Name) ,
(Password) - Y1Y2,
(V=Challenge) - Y3Y4.
IP-
IPv4 , . 4, IP-, .
. 4
IP- | . | ||||
A | 0.0.0.0 | 127.0.0.0 | 2 7 2 | 2 24 2 | |
B | 128.0.0.0 | 191.255.0.0 | 2 14 2 | 2 16 2 | |
C | 192.0.0.0 | 223.255.255.0 | 2 21 2 | 2 8 2 | |
D | 224.0.0.0 | 255.255.255.255 | |||
E | 240.0.0.0 | 255.255.255.255 | .+ |
, , .
IPv4 .
1. 0.0.0.0 , 127.0.0.0 ( ), 126.
2. IP- , . 1.1, .
3. 1 ( ), . 2 , 2.
4. , . . 10.0.0.0, 172.16.0.0 172.31.0.0, 192.168.0.0. 192.168.255.255.
5. D -- - . , , (Internet Group Management Protocol IGMP) . , , . , .
|
|
6. .
IP- , . 1.1. , , . IP-. , 255.0.0.0 ( 11111111.00000000.00000000.00000000), 255.255.0.0 (11111111.11111111.00000000.00000000), 255.255.255.0 (11111111.11111111.11111111.00000000).
. , 8000 . (254 ) , (65534) . , . .
, , 135.38.0.0 ( , 255.255.0.0). 16 16 . 8000 , 13 (213 = 8192), , 16 13 = 3 . 11111111.11111111. 111 00000.00000000 255.255.224.0 ( ).
(. 5).
. 5
10000111 00100110 00100000 00000000 135. 38. 32. 0 | |
10000111 00100110 01000000 00000000 135. 38. 64. 0 | |
10000111 00100110 01100000 00000000 135. 38. 96. 0 | |
10000111 00100110 10000000 00000000 135. 38. 128. 0 | |
10000111 00100110 10100000 00000000 135. 38. 160. 0 | |
10000111 00100110 11000000 00000000 135. 38. 192. 0 | |
135.38.0.0 135.38.224.0 , .. 135.38.0.0 , 135.38.224.0 . 6 (, 135.38.32.0) , 5 .
135.38.32.0 . 3.
135.38.32.0 R (. 3) (. 6).
.6
(Destination) | (Subnet Mask) | (Next Hop) | (Interface) | (Metric) |
135.38.32.0 | 255.255.224.0 | 0.0.0.0 | s1 | |
Default | 0.0.0.0 | s2 |
.
1. (Destination) IP- .
2. (Subnet Mask) IP-, .
3. (Next Hop) IP- , .
4. (Interface) , , .
5. (Metric) . .
.
1. IP- Ȕ . Ȕ: 0+0=0, 0+1=0, 1+0=0, 1+1=1.
2. IP- . s1.
|
|
3. , 1, , .
4. 135.38.32.0 s2.
, IP- : 135.38.16.15, 135.38.56.211, 135.38.92.10. ?
Ȕ IP- ,
IP=135.38.16.15 à 10000111. 00100110. 00001000. 00001111
Mask= 255.255.224.0 à 11111111. 11111111. 11100000. 00000000
------------------------------------------------------
Destination = 10000111. 00100110. 00000000. 00000000 2 à 135. 38.0.0.
, .
IP=135.38.56.211 à 10000111. 00100110. 00111000. 11010011
Mask= 255.255.224.0 à 11111111. 11111111. 11100000. 00000000
------------------------------------------------------
Destination = 10000111. 00100110. 00100000. 00000000 2 à 135. 38.32.0.
s1.
IP=135.38.92.10 à 10000111. 00100110. 01011100. 00001010
Mask= 255.255.224.0 à 11111111. 11111111. 11100000. 00000000
------------------------------------------------------
Destination = 10000111. 00100110. 01000000. 00000000 2 à 135. 38.64.0.
, .
5.