it's a ACL a layer 4 transport layer protocol ?

yrwinsyrwins Posts: 81Member ■■□□□□□□□□
it's a ACL a layer 4 transport layer protocol ?

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  • fearlessfreap24fearlessfreap24 Posts: 10Member ■□□□□□□□□□
    I believe an ACL resides in Layer 3. A normal ACL can block a host or block of IP address which are layer 3. An Extended ACL can block a protocol but still uses IP address to do so.
  • yrwinsyrwins Posts: 81Member ■■□□□□□□□□
    thanks.
  • james43026james43026 Posts: 303Member
    From a network point of view, an ACL can go up to layer 4, if we are talking about extended ACL's.
  • clarsonclarson Posts: 885Member ■■■■□□□□□□
    ip acl is layer 3
    an extended acl is either layer 3 or 4
  • NiceRouteNiceRoute Posts: 8Member ■□□□□□□□□□
    If it can block logical ports, then it can be referred to as working at layer 4.
  • OctalDumpOctalDump Posts: 1,722Member
    No. An ACL is not a protocol. Cisco ACLs can modify the behaviour of traffic from layer 2 up. Typically at CCNA level you deal with ACLs that modifying traffic at layer 3 and 4. Eg, block all traffic from this IP (layer 3), or allow access to only these ports (layer 4) at this IP.
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  • TheFORCETheFORCE Posts: 2,235Member ■■■■■■■■□□
    OctalDump wrote: »
    No. An ACL is not a protocol. Cisco ACLs can modify the behaviour of traffic from layer 2 up. Typically at CCNA level you deal with ACLs that modifying traffic at layer 3 and 4. Eg, block all traffic from this IP (layer 3), or allow access to only these ports (layer 4) at this IP.

    About to say that, ACL's are not protocols. You can have ACL is many different type of devices.
  • Cisco InfernoCisco Inferno Posts: 1,035Member ■■■■■□□□□□
    standard ACL's block L3 traffic based on IP address. Extended ACL's can filter things based on L4 Port info on top of that.
    ex. Blocking Port 80 web traffic to a specific subnet. (like a kiosk pc or something)
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