From: DuBell, Robert ITC J633CT1 (dubell@xxxxxxxxx)
Date: Wed May 09 2001 - 08:13:06 GMT-3
Just logged in so don't know if this has been answered yet. The MAC address
for multicast is in fact 01:00:5e:xx:xx:xx where the low order 23 bits from
the class D ip address, for example, 224.0.0.5 (OSPF Hello packets) would
have a mac of 01:00:5e:00:00:05 as the multicast MAC address, the range for
multicasing is 01005e000000 through 01005e7fffff....Bobdu1
-----Original Message-----
From: Devender Singh [mailto:devender.singh@cmc.cwo.net.au]
Sent: Tuesday, May 08, 2001 7:36 PM
To: Fred Ingham; Tariq Sharif; Ccielab@Groupstudy. Com
Subject: RE: MAC Address Filter Examples
Fred,
I thought the mac addresses for multicast is 01-00-5e-xx-xx-xx. But
obviously it seems like I am wrong.
But Tariq's email and your response it seems like multicast mac addresses
mostly are
1) 01-00-xx-xx-xx-xx
2) but some protocols can also have first octet to be XXXXXXX1- and the
second octet to XXXXXXXX
Will you be kind enough to clarify this for me.
Devender Singh
BE(Hons), CCNP
IP Solution Specialist
-----Original Message-----
From: Fred Ingham [mailto:fningham@worldnet.att.net]
Sent: Wednesday, 11 April 2001 5:51
To: Tariq Sharif; Ccielab@Groupstudy. Com
Subject: Re: MAC Address Filter Examples
Tariq: feff will catch any odd number in the second nibble. There are
protocols that use multicast with an address other than 01 but they are
all odd.
Cheers, Fred
Tariq Sharif wrote:
>
> Sorry guys, I was after generic MAC filtering. e.g. with IRB etc not DLSw+
>
> Ok, here is the question I have:
>
> R2 has IRB running with 1 Ethernet interface, serial & 1 BVI. Configure an
> MAC Address filter on R2 so that it will block broadcast and multicast
> packets for a host on its Ethernet Bridge segment. The filter is shown
> below. Now why is 1st line in the filter with mask of "feff". I know we
need
> to match multicasts which start with "0100" but shouldn't the mask for
this
> portion be "f0ff" rather than "feff"?
>
> hostname R2
> bridge irb
> interface Ethernet1/0
> no ip address
> bridge-group 1
> bridge-group 1 input-pattern-list 1100
> !
> interface Serial1/0
> ip address 140.1.5.2 255.255.255.0
> interface BVI1
> ip address 140.1.3.2 255.255.255.240
> !
> bridge 1 protocol ieee
> bridge 1 route ip
> !
> access-list 1100 deny 0000.0000.0000 ffff.ffff.ffff 0100.0000.0000
> feff.ffff.ffff
> access-list 1100 deny 0000.0000.0000 ffff.ffff.ffff ffff.ffff.ffff
> 0000.0000.0000
> access-list 1100 permit 0000.0000.0000 ffff.ffff.ffff 0000.0000.0000
> ffff.ffff.ffff
>
> -----Original Message-----
> From: Patrick Murphy [mailto:pjm@roadrunner.nf.net]
> Sent: 10 April 2001 16:04
> To: Tariq Sharif; Ccielab@Groupstudy. Com
> Subject: Re: MAC Address Filter Examples
>
> http://www.cisco.com/warp/public/697/dlswfilter.shtml
>
> The best I have seen yet!
>
> Patrick
>
> ----- Original Message -----
> From: "Tariq Sharif" <tariq_sharif@yahoo.com>
> To: "Ccielab@Groupstudy. Com" <ccielab@groupstudy.com>
> Sent: Tuesday, April 10, 2001 11:49 AM
> Subject: MAC Address Filter Examples
>
> > Does anyone know where I can get MAC Address Filter Examples or info?
> >
> > Many thanks & regards.
> >
> > Tariq Sharif
> >
> > [GroupStudy.com removed an attachment of type application/ms-tnef which
> had a name of winmail.dat]
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