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Access List question

When one applies an Access-list to an out interface of the ethernet connection to the LAN on a router does that cover the traffic going out to the LAN or the traffic going out of the LAN to the router?

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Accepted Solutions
VIP Super Bronze

Re: Access List question

John,

Here are some definitions:

When you refer to a router, these terms have these meanings.

  • Out—Traffic that has already been through the router and leaves the interface. The source is where it has been, on the other side of the router, and the destination is where it goes.

  • In—Traffic that arrives on the interface and then goes through the router. The source is where it has been and the destination is where it goes, on the other side of the router.

  • Inbound —If the access list is inbound, when the router receives a packet, the Cisco IOS software checks the criteria statements of the access list for a match. If the packet is permitted, the software continues to process the packet. If the packet is denied, the software discards the packet.

  • Outbound—If the access list is outbound, after the software receives and routes a packet to the outbound interface, the software checks the criteria statements of the access list for a match. If the packet is permitted, the software transmits the packet. If the packet is denied, the software discards the packet.

More info:

http://www.cisco.com/en/US/products/sw/secursw/ps1018/products_tech_note09186a00800a5b9a.shtml#sourcedefine

HTH

Reza

    Re: Access List question

    When one applies an
    Access-list to an out interface of the ethernet connection to the LAN
    on a router does that cover the traffic going out to the LAN or the
    traffic going out of the LAN to the router?

    Hi,

    An access-list applied outbound to  interface filters traffic going TO machines on that interface or segment.

    An access-list applied inbound to interface filters traffic coming FROM machines on that interface or segment.

    Hope to Help !!

    Ganesh.H

    Remember to rate the helpful post

    3 REPLIES
    VIP Super Bronze

    Re: Access List question

    John,

    Here are some definitions:

    When you refer to a router, these terms have these meanings.

    • Out—Traffic that has already been through the router and leaves the interface. The source is where it has been, on the other side of the router, and the destination is where it goes.

    • In—Traffic that arrives on the interface and then goes through the router. The source is where it has been and the destination is where it goes, on the other side of the router.

    • Inbound —If the access list is inbound, when the router receives a packet, the Cisco IOS software checks the criteria statements of the access list for a match. If the packet is permitted, the software continues to process the packet. If the packet is denied, the software discards the packet.

    • Outbound—If the access list is outbound, after the software receives and routes a packet to the outbound interface, the software checks the criteria statements of the access list for a match. If the packet is permitted, the software transmits the packet. If the packet is denied, the software discards the packet.

    More info:

    http://www.cisco.com/en/US/products/sw/secursw/ps1018/products_tech_note09186a00800a5b9a.shtml#sourcedefine

    HTH

    Reza

      Re: Access List question

      When one applies an
      Access-list to an out interface of the ethernet connection to the LAN
      on a router does that cover the traffic going out to the LAN or the
      traffic going out of the LAN to the router?

      Hi,

      An access-list applied outbound to  interface filters traffic going TO machines on that interface or segment.

      An access-list applied inbound to interface filters traffic coming FROM machines on that interface or segment.

      Hope to Help !!

      Ganesh.H

      Remember to rate the helpful post

      New Member

      Re: Access List question

      Thanks for the reply. It was very helpful.

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