how do we know what ACL configuration mean? an example access-list 89 permit tcp host any eq www? does this allow the traffic from the host inside? i'm a bit confused. any help would be appreciated

  • Configuration statements are platform specific, so please be clear on which platform and software you're talking about.
    – Teun Vink
    May 19 '20 at 15:17
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can post and accept your own answer.
    – Ron Maupin
    Dec 17 '20 at 17:42

That depends on how the ACL is applied to interfaces. In your case, you're probably right; but you should examine the rest of your config to be sure.

Here is a good primer on Cisco ACL configuration and the relevant reference material on the related ip access-group command, which is used to apply an ACL to an interface.

  • 89 : line number for editing or ACL name, depending on platform
  • permit : permit the following packets
  • tcp : packets need to contain TCP
  • host : single source address
  • any : destination address
  • eq www : qualifies the any for destination port 80 (HTTP)

So, if this ACL entry (ACE) is applied ingress from the source address or egress towards the HTTP server(s) in question it permits the source to connect to and send a request to the web server.

You should examine the full ACL to make sense of it. Especially the implicit deny any any at its end is very often overlooked.

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