From: ccie2be (ccie2be@nyc.rr.com)
Date: Mon Apr 26 2004 - 13:42:18 GMT-3
Bob,
Thanks, this is fantastic. I'm in the process of making some notes to
myself to highlight the Gotcha's I need to be aware of with the 3550.
It sounds like based on what you've told me, I can conclude re: 3550 acl's
1) They work essentially the same way as they do when configured on router
interfaces
2) They can applied to any type of 3550 port (L2 phy access, L3 routed
interface, trunk, phy port that's part of etherchannel, or SVI ) the same
way they would be applied to an interface on a router ie they do NOT have to
be applied via the creation of the MQC ( class, policy, service) although
doing it that way is OK also.
3) The ONE exception is that if the acl is to be applied to a L2 access
port, it must be ONLY in the inbound direction.
One last question while we're on the topic of acl's:
Re: SVI's: Since an SVI is a logical interface, what meaning does the
direction (In or OUT) have as applied to a SVI? For example, suppose this
is my config. And, ports fa0/1 - 3 are in vlan 30.
access-list 3 permit 36.0.0.0
int vlan 30
ip addr x.x.x.x
ip access-group 3 in
Will traffic coming *in* from ports fa0/1 - 3 that isn't permitted by acl 3
be denied and not passed to other routed interfaces on the 3550 or will
traffic going in the other direction, coming in through routed interfaces
and heading to svi 30 be denied? Or, does this question not make sense?
Thanks again, Tim
----- Original Message -----
From: "Bob Sinclair" <bsinclair@netmasterclass.net>
To: "ccie2be" <ccie2be@nyc.rr.com>; "Group Study" <ccielab@groupstudy.com>
Sent: Monday, April 26, 2004 12:04 PM
Subject: Re: Correction: 3550 - ip acl's on trunks
> The docs seem to use the term "etherchannel interface" to refer to either
a
> L2 or L3 Interface Port-Channel.
>
> Also from what I can gather, a "port acl" is an access-list applied to a
> layer 2 port, whereas a "router-acl" is applied to a layer 3 port (routed,
> L3 Po, or Int VLAN). However there are some other differences, e.g.,
port
> acls can only be applied inbound.
>
> I have tested your config re acl on trunk, and it does seem to work as
> advertised.
>
> I take along a Cat3550 "virtually" everywhere I go, so let me know if i
can
> test something for you.
>
> HTH,
>
> Bob Sinclair
> CCIE #10427, CISSP, MCSE
> www.netmasterclass.net
>
> ----- Original Message -----
> From: "ccie2be" <ccie2be@nyc.rr.com>
> To: "Group Study" <ccielab@groupstudy.com>; "Bob Sinclair"
> <bsinclair@netmasterclass.net>
> Sent: Monday, April 26, 2004 11:52 AM
> Subject: Re: Correction: 3550 - ip acl's on trunks
>
>
> > Hi Bob,
> >
> > Thanks for getting back to me. I appreciate it. Yes, I agree the
> > documentation is sometimes a bit confusing - at least for me. And,
> > unfortunately, since I don't have ready access to a couple of 3550's, I
> > can't easily or quickly experiment on the switches to test out my
> questions.
> >
> > Just to make sure I understand what you're saying, can I restate this as
> > follows?
> >
> > A "PO" refers to just a regular L2 port?
> >
> > The only distinction you're making in your 1st post when you say "port
> acl"
> > vs "router acl" is the type of port, L2 vs L3?
> >
> > And, as far as acl's applied to trunk ports, you're saying it will work
> just
> > as if the port were a regular L2 or L3 port.
> >
> > For example, is this config OK?
> >
> > access-list 1 deny 10.0.0.0
> > access-list 1 permit ip any any
> >
> > int fa0/4
> > switchport mode trunk
> > access-group 1 in
> >
> > So, as a result, all traffic from 10.0.0.0 will be denied regardless of
> what
> > vlan the pkt rides in?
> >
> > Or, do I need to use the MQC structure and the Per_Port Per-Vlan
construct
> > show in the manual on page 27 34?
> >
> > Or, am I way out in left field and don't have a clue?
> >
> > Thanks, Tim
> >
> > ----- Original Message -----
> > From: "Bob Sinclair" <bsinclair@netmasterclass.net>
> > To: "Tim Last" <packtmon@yahoo.com>; "Group Study"
> <ccielab@groupstudy.com>
> > Sent: Monday, April 26, 2004 10:58 AM
> > Subject: Correction: 3550 - ip acl's on trunks
> >
> >
> > > Tim,
> > >
> > > After more further reflection, it looks like applying port acls to
> > physical
> > > ports in an etherchannel is supported. What is not supported is
> applying
> > an
> > > access-list to a L2 PortChannel Interface. When the docs refer to an
> > > "Etherchannel interface", they appear to mean the PortChannel
Interface
> > (L2
> > > or L3), not the physical ports in the channel.
> > >
> > >
> > > Bob Sinclair
> > > CCIE #10427, CISSP, MCSE
> > > www.netmasterclass.net
> > >
> > > ----- Original Message -----
> > > From: "Bob Sinclair" <bsinclair@netmasterclass.net>
> > > To: "Tim Last" <packtmon@yahoo.com>; "Group Study"
> > <ccielab@groupstudy.com>
> > > Sent: Monday, April 26, 2004 10:43 AM
> > > Subject: Re: 3550 - ip acl's on trunks
> > >
> > >
> > > > Tim,
> > > >
> > > > The documentation says port acls are not permitted on (L2)
> etherchannel
> > > > interfaces. Router acls are allowed on PO interfaces. I would
take
> > > this
> > > > as sound advice, though I have found that port acls applied to L2
> > > > etherchannel interfaces are effective.
> > > >
> > > > Docs say that port acls applied to trunk ports will filter all vlans
> on
> > > the
> > > > trunk, which appears to work in practice.
> > > >
> > > > HTH,
> > > >
> > > > Bob Sinclair
> > > > CCIE #10427, CISSP, MCSE
> > > > www.netmasterclass.net
> > > >
> > > > ----- Original Message -----
> > > > From: "Tim Last" <packtmon@yahoo.com>
> > > > To: "Group Study" <ccielab@groupstudy.com>
> > > > Sent: Monday, April 26, 2004 10:13 AM
> > > > Subject: 3550 - ip acl's on trunks
> > > >
> > > >
> > > > > Hi guys,
> > > > >
> > > > > I know that standard and extended ip acl's work without any
> additional
> > > > configuration statements on regular Cat 3550 L2 access ports
(assuming
> > the
> > > > acl isn't being used for QoS purposes).
> > > > >
> > > > > Is this also true if the port is a trunk or if ports have been
> grouped
> > > > into an etherchannel?
> > > > >
> > > > > Also, can ip acl's be applied to SVI's?
> > > > >
> > > > > Thanks in advanced, Tim
> > > > >
> > > > >
> > > > > ---------------------------------
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