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