CCNA 3 - Capitulo 4.1

CCNA 3 - Capitulo 4.1

1. 2. WILDCARD MASKs IN ACLs

   • WILDCARD MASK TYPES
     • 1. WILDCARD TO SPECIFIED HOST
       • R1(CONFIG)# ACCESS-LIST 10 PERMIT 192.168.1.1 0.0.0.0
       • MAK CONSISTING OF ALL ZEROES 0.0.0.0 IS RIQUERED
     • 2. WILDCARD TO MATCH A SUBNET
       • ALL HOSTS IN SUBNET
       • R1(CONFIG)# ACCESS-LIST 10 PERMIT 192.168.1.0 0.0.0.255
         • FIRTST THREE OCTETS UST MATCH EXACTLY BYT THE FOURTH OCTED DOES NOT
     • WILDCARD TO MATCH A RANGE - IPV4
       • PERMIT ALL HOSTS IN THE 192.168.16.0/24 , 192.168.17.0/24 , 192.168,31.0
         • R1(CONFIG)# ACCESS-LIST 10 PERMIT 192.168.16.0 0.0.15.255 (WILDCARD)
           • WILL BE PERMITS ALL HOSTS IS THE 192.168.16.0/24 TO 192.168.31.0/24
           • NETMASK 255.255.240.0
   • WHERE ARE WILDCARDS USED?
     • OSPF ROUTING PROTOCOL & ACE
   • IPV4 ACE - USE WILDCARD a 32 BITS
     • TO DETERMINE WHICH BITS OF THE ADDRESS TO EXAME FOR A MATCH
   • NOTES : SIMILAR TO A SUBNET MASK , HOWEVER , THE REVERSE IS TRUE
     • WILDCARD MASK bit 0
       • MACH THE CORRESPONDING
     • WILDCARD MASK bit 1
       • IGNORE THE CORRESPONDING
     • 0 = TRUE
   • WILDCARD MASK CALCULATION
     • SHORCURT METHOD ?
       • SUBTRACT THE MASK FROM 255.255.255.255
         • EXAMPLE 1 - PERMITE ACCESS TO ALL USERS IN THE 192.168.3.0/24
           • 255.255.255.255 - 255.255.255.0 0.0.0.255
             • R1(CONFIG)# ACCESS-LIST 10 PERMIT 192.168.3.0 0.0.0.255
         • EXAMPLE 2 - PERMITE NETWORK ACCESS FOR 14 USER IN THE SUBNET 192.168.32.28
           • 255.255.255.255 - 255.255.255.224 0.0.0.15
             • R1(CONFIG)# ACCESS-LIST 10 PERMIT 192.168.3.0 0.0.0.15
         • EXAMPLE 4 - TO PERMITE RANGE BETWEEN 192.168.16.0/24 TO 192.168.31.0/24
           • FIRST SUMMARIZED AS 192.168.16.0/20
           • AFTER , YOU SUBTRACT NETMASK FROM TO OBTAIN WILDCARD
             • 255.255.255 - 255.255.254.0 0.0.15.255
               • R1(CONFIG)# ACCESS-LIST 10 PERMIT 192.168.3.0 0.0.15.255
         • EXAMPLE 3 - TO PERMITE NETWORKS 192.168.10.0/24 AND 192.168.11.0/24
           • FIRST SUMMARIZED AS 192.168.10.0/23
           • AFTER , YOU SUBTRACT NETMASK FROM TO OBTAIN WILDCARD
             • 255.255.255.255 - 255.255.254.0 0.0.1.255
               • R1(CONFIG)# ACCESS-LIST 10 PERMIT 192.168.3.0 0.0.1.255
   • WILDCARD MASK KEYWORDS
     • REPRESENTATIONS OF BINARY WILDCARD WITH TWO KEYWORDS
       • HOST KEYWORD
         • SUBSTITUTES FOR 0.0.0.0 MASK
         • TO FILTER JUST ONE HOST ADDRESS
         • EXAMPLE - PERMIT ONLY THE 192.168.10.10
           • R1(CONFIG)# ACCESS-LIST 10 PERMIT 192.168.10.10 0.0.0.0
           • R1(CONFIG)# ACCESS-LIST 10 PERMIT HOST 192.168.10.10
       • ANY KEYWORD
         • SUBSTITUTES FOR 255.255.255.255 MASK
           • IGNORE THE ENTIRE IPV4 OR TO ACCEPT ANY ADDRESS
         • EXAMPLE - PERMIT ALL HOSTS
           • R1(CONFIG)# ACCESS-LIST 11 PERMIT 0.0.0.0 255.255.255.255
           • R1(CONFIG)# ACCESS-LIST 11 PERMIT ANY

2. ACCESS CONTROL LIST - ACL