IP ACCESS-LIST

ACCESS LIST IS WORKS LIKE A FIREWALL,ACCESS-LIST IS USED TO PROTECT YOUR NETWORK FROM UNAUTHORISED CONNECTIONS.

USING ACCESS LIST YOU CAN RESTRICT/ALLOW A PARTICULAR NETWORK OR HOST,

ACCESS-LIST TYPES:

1:STANDARD ACL (1-99)
ONLY DEFINE THE SOURCE ADDRESS

2:EXTENDED ACL (100-199)
DEFINE SOURCE AND DESTINATION AND PORT NO OR PROTOCOL


DENY = NOT ALLOW (RESTRICTION)
PERMIT= ALLOWED

(CONFIG)#ACCESS-LIST 10 DENY HOST 10.0.0.2
(CONFIG)#ACCESS-LIST 10 PERMIT HOST 10.0.0.3

DENY =99%
PERMIT=1%

PERMIT =INVITATION
IMPLICIT DENY


HOW TO APPLY

STEP 1: CREATE A ACCESS-LIST(CREATE RULES)
STEP2: APPLY ON A INTERFACE(APPLY RULES)


(CONFIG)#ACCESS-LIST 3 DENY 192.168.1.0 0.0.0.255
(CONFIG)#ACCESS-LIST 3 DENY 0.0.0.0 0.0.0.0
(CONFIG)#ACCESS-LIST 3 DENY ANY
(CONFIG)#ACCESS-LIST 3 PERMIT ANY

(config)#int f0/0
(config)#ip access-group 10 out

in=inbound recieve the call
out=outbound make a call

out=the packet must pass a routing process
in=the packet not pass a routing process

0=MUST MATCH
255=DON'T CARE

Color Coding of UTP

STRAIGHT CABLE: BOTH END SAME
CROSS CABLE : 1236    AND 3612
ROLLED CABLE:ALL PAIRS ARE DIFFRENT
1236
6321

1 ORANGE-WHITE (TX+)
2 ORANGE (TX-)
3 GREEN-WHITE (RX+)
4 BLUE
5 BLUE-WHITE
6 GREEN (RX-)
7 BROWN-WHITE
8 BROWN


Only 4 Wires is used to make data Transfer , Remaining wires send Dummy signals.

DHCP

DYNAMIC HOST CONFIGURATION PROTOCOL

DHCP IS A PROTOCOL USED TO ASSIGN IP ADDRESS DYNAMICALLY.


DHCP IS USES A LEASE AND POOL OF IP ADDRESS

DHCP USES 4 TYPES OF PACKETS

1 DHCP DISCOVER PACKET:

2 DHCP OFFER:

3 DHCP REQUEST PACKET :

4 DHCP ACK:


CLIENT SERVER

NO IP ADDRESS POOL OF IP (RANGE OF IP ADD)
MAC ADDRESS
1:SEND THE DISCOVER PACKET TO SEARCH THE DHCP SERVER .
2:IF HAVE A VALID DHCP SERVER LOCATED , DHCP SERVER SEND A OFFER PACKET TO THE CLIENT.
(IP ADDRESS/SUBNET MASK+DNS SERVER ADDRESS+DEFAULT GATEWAY+DOMAIN NAME+LEASE)
3:IF DHCP IS NOT FOUND , CLIENT REQUEST FOR APIPA (AUTOMATIC PRIVATE IP ADDRESS) TO OBTAIN AN IP ADDRESS AUTOMATICALLY.
(169.254.0.1-------169.254.255.255)CLASS B
4:CLIENT USESE DHCP REQUEST PACKET TO DHCP IF THE LEASE IS ABOUT TO EXPIRED.
5:DHCP SERVER PROVIDE THE ACKNOWLEDGEMENT PACKET TO CLIENT WITH A NEW LEASE +IP+DNS+DG+DOMAIN.

NOTE: DHCP USES THE PORT NO 67/68 OF UDP

WAN TERMS

WAN PROTOCOLS

CPE=CUSTOMER PRIMISES EQUIPMENT
IS A DEVICE THAT IS INSTALLED BY ISP TO THE CUSTOMER SITE

CO=CENTRAL OFFICE
IS A CENTRAL POINT ,WHERE ALL CONNECTIONS ARE CREATED AND MANAGE CONNECTIONS CENTRALLY.

DP=DEMACATION POINT
IS THE POINT WHERE ISP'S RESPOSIBILTIES ENDS

TOLL-NETWORK: IS THE DISTANCE THAT CONNECTS ALL CENTRAL OFFICE TOGETHER.

LOCAL LOOP: IS THE DISTANCE BETWEEN DEMARCATION POINT AND THE NEAREST CENTRAL OFFICE OR SWITCHING STATIONS.

DNS (DOMAIN NAME SYSTEM)

DNS COMPONENTS

DNS CLIENT( IS A SERVICE THAT IS USED FOR RESOLVING)CONTAINS RESOLVER CACHE,
LOCATED ON CLIENT AND SERVER BOTH

DNS SERVER:LOCATED ON SERVER ONLY


DNS CLIENT SERVICE : XP,2000,2003,2008
DNS SERVER : WINDOWS SEVER 2000,2003,2008


DNS IS INSTALLED IF WE INSTALLED ACTIVE DIRECTORY , AD WIZARD ASK YOU FOR INSTALLING DNS ,BECAUSE ACTIVE-DIRECTORY IS TIGHTLY COUPLED WITH DNS.

DNS : 2 METHODS

1:WITH AD
2:WITHOUT AD

AD REQUIRED DNS(MUST)
DNS NOT REQUIRED AD

MCTS PAPERS

70-620 : windows vista configuring

70-640 : windows server 2008 active directory configuring

70-642: windows server 2008 network infrastructure configuring

70-643 : windows server 2008 applications infrastructure

70-236: configuring exchange server 2007

DNS RECORDS TYPES

HOST(A):REPRESENT A HOST OR COMPUTER ON THE NETWORK.

PTR(POINTER):ALWAYS LOCATED ON REVERSE LOOKUP ZONE,USED FOR IP TO HOST RESOLVING.

SOA(START OF AUTHORITY):IS THE FIRST RECORD IN ANY DNS SERVER,TO AUTHORISE DNS FOR THAT ZONE.

NS(NAME SERVER):IS USED TO IDENTIFY A DNS SERVER ON YOUR NETWORK.

MX(MAIL EXCHANGE):IS REPRESENT AN SMTP MAIL SERVER ON YOUR NETWORK.

SRV(SERVICE LOCATION RECORD):IS LOCATED ON AD INTEGRATED ZONE,TO LOCATE A DOMAIN CONTROLLER ON THE NETWORK AND LOCATE A SERVICE FOR THE DOMAIN CONTROLLER.

CNAME(ALIAS): USED TO REPRESENT A HOST TO ANOTHER HOST

EXAMPLE: IF YOU TYPE GOOGLE.COM
YOU ARE REDIRECTED TO GOOGLE.CO.IN

DNS QUERIES:2 TYPES

RECURSIVE QUERY:
FIND THE RECORDS TO OHTER DNS SERVERS. IF RECORDS IS NOT FOUND TO ITS FORWARD AND REVERSE LOKUP ZONES.

ITERATIVE QUERY:is a query that is dns client ask the dns server to provide the best answer . dns server check its forward lookup zone and reverse lookup zone to search the answer for the query ,if host is not found ,it uses the forwarder to search the result. it lookup its parent domain or even root hits to search the query.