From: Frank B (frank@xxxxxxxxxxxx)
Date: Wed Apr 17 2002 - 20:29:00 GMT-3
If you filter this mac address somehwere in the path between the two
Ethernet segments (after it's picked up by DLSW) you're correct.
But DLSW coverts the mac back to canonical if the destination is an
Ethernet segment. So, "what if" you were filtering traffic inbound to
the destination segment from a DLSW peer connection across a WAN such
as:
router(config-if)#bridge-group 2 input-address-list 700
Is the conversion back to canonical made at point this already? What
would be the proper address format for access-list 700? Does anyone
know? Please copy me on the reply if you do.
Frank
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Lupi, Guy
Sent: Wednesday, April 17, 2002 11:07 AM
To: 'Adam Atkinson'; CCIE Groupstudy
Subject: RE: bitflipping in dlsw - when?
Someone will correct me if I am wrong I am sure, but I believe that even
if
the filtering is ethernet to ethernet the mac address must be swapped.
When
looking at an ethernet router that has dlsw configured, even the local
mac
addresses that it picks up will be shown in non-canonical format. So if
your workstation has mac address 1111.1111.1111, it will appear on the
local
dlsw router as 8888.8888.8888. So if filtering for a mac address that
is on
an Ethernet segment, you always bitswap it when you put it in the
filter.
Below is an example of what I am talking about, r2 is a dlsw router and
r8
is on the Ethernet segment. R8's show interface is below, notice the
mac
address, and then look at the dlsw reach information on r2. R2 has that
mac
address in non canonical format.
r8#sh int e0/0
Ethernet0/0 is up, line protocol is up
Hardware is AmdP2, address is 0002.16d9.c460 (bia 0002.16d9.c460)
r2----E0----r8
r2#sh dlsw reach
DLSw Local MAC address reachability cache list
Mac Addr status Loc. port rif
0040.689b.2306 FOUND LOCAL TBridge-001 --no rif--
DLSw Remote MAC address reachability cache list
Mac Addr status Loc. peer
DLSw Local NetBIOS Name reachability cache list
NetBIOS Name status Loc. port rif
DLSw Remote NetBIOS Name reachability cache list
NetBIOS Name status Loc. peer
r2#
-----Original Message-----
From: Adam Atkinson [mailto:ghira@mistral.co.uk]
Sent: Wednesday, April 17, 2002 2:55 PM
To: CCIE Groupstudy
Subject: bitflipping in dlsw - when?
I'm feeling less than clear on _when_ I need to to bitflip the MAC
address I'm given in a dlsw-related assignment.
If the mac address is from an ethernet segment, and I'm filteing on a TR
segment, I bitflip.
Are there other situations where I'd need to do this?
-- Adam Atkinson (ghira@mistral.co.uk)
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