Stupid Cisco ACL question
dorn at hetzel.org
Thu Apr 21 19:17:31 UTC 2011
On Thu, Apr 21, 2011 at 3:13 PM, <up at 3.am> wrote:
> Ok, I've done a lot of Cisco standard and extended ACLs, but I do not
> understand why the following does not work the way I think it should.
> Near the end of this extended named ACL, I have the following:
> permit tcp any eq 443 any
Don't you want:
permit tcp any any eq 443
Since you want the incoming traffic to have 443 as the destination port, not
> permit tcp any eq 80 any
> deny ip any host 220.127.116.11
> permit ip any any
> This is applied to an inbound interface(s). We want anybody outside to be
> able to reach ports 80 and 443 of any host on our network, no matter what,
> then block ALL other access to select hosts, such as 18.104.22.168, even ICMP.
> However, as soon as I apply this rule to the interface, ports 80 and 443
> of that host become unreachable. A telnet to 22.214.171.124 443 gets "Connection
> refused" until I tear out the deny ACL above. I even tried adding udp for
> both ports, to no avail.
> I had always thought that these ACLs were processed in order, so that the
> explicit permit statement, though limited to a specific protocol but for
> all hosts, gets considered before the explicit deny statement for all IP
> to a particular host. What did I forget to consider?
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