ACL

ACL

1. Standard

   • 1-99, 1300-1999
   • Source IP only
   • Logic
     • First match is applied
     • Implicit Deny at the end
       • Unless "access-list X permit any"
   • Syntax
     • access-list {1-99 | 1300-1999} {permit | deny} matching_parameters
     • (at the interface): ip access-group {1-99 | 1300-1999} {in | out}
     • access-list {1-99 | 1300-1999} remark text_to_remember_what_the_ACL_do
   • Wildcard Masc
     • 0 = Normal, 255 = Ignore
     • Tricks
       • masc 255.255.0.0 = WC masc 0.0.255.255
       • masc /27 = WC masc 0.0.31.255
         • 255 - 224 = 31
       • 192.168.0.0 WC 0.0.3.255 = from IP 192.168.0.0 till 192.168.3.255
   • Should be placed near destination

2. Extended

   • 100-199, 2000-2699
   • More Versatility
     • Source & Destination IP
     • Source & Destination Port
     • Others

3. Named

4. Improved Editing with Sequence Numbers