From: James Ventre (messageboard@ventrefamily.com)
Date: Thu Apr 21 2005 - 14:48:31 GMT-3
>Also keep in mind that CDP and VTP will use the same D-MAC.
To elaborate on this a bit more.
SNAP Protocol Type:
CDP = 0x2000
VTP = 0x2003
DTP = 0x2004
James
James Ventre wrote:
I take it that the first entry is the one for vtp, right?
In this instance yes, but don't count on that always being the case.
That's why I suggest you just memorize it.
Besides that entry are there any others that are special? Like STP?
DTP? CDP? HSRP? etc.?
802.1d BPDU = 0180.c200.0000
PVST BPDU (native vlan) = 0100.0ccc.cccd
You can calculate the one for the tagged PVST vlan ID ... check CCO for
that.
I'm sure there are more - but I can't remember them off the top of my
head.
Also keep in mind that CDP and VTP will use the same D-MAC. You block
one ..... and you might block the other - don't create your own "Rat
Holes" :)
James
ccie2be wrote:
Hey James,
Thanks for show us that table. I take it that the first entry is the one
for vtp, right?
Besides that entry are there any others that are special? Like STP? DTP?
CDP? HSRP? etc.?
Thanks again, Tim
-----Original Message-----
From: nobody@groupstudy.com [ mailto:nobody@groupstudy.com ] On Behalf Of
James Ventre
Sent: Thursday, April 21, 2005 12:39 PM
To: ccielab@groupstudy.com Subject: Re: blocking VTP traffic
You'll have to remember something about it .... one way or another.
It's either how you figure it out (memorize the command and what to look
for) or just memorize the MAC. But you've got 2 options.
1. Remember that the multicast byte is turned on ... and the 2nd half is
all c's.
2. Figure it out from the below list.
SWITCH>sh mac-address-table vl 1
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
Vlan Mac Address Type Por
---- ----------- -------- ---
1 0100.0ccc.cccc STATIC CPU
1 0100.0ccc.cccd STATIC CPU
1 0180.c200.0000 STATIC CPU
1 0180.c200.0001 STATIC CPU
1 0180.c200.0002 STATIC CPU
1 0180.c200.0003 STATIC CPU
1 0180.c200.0004 STATIC CPU
1 0180.c200.0005 STATIC CPU
1 0180.c200.0006 STATIC CPU
1 0180.c200.0007 STATIC CPU
1 0180.c200.0008 STATIC CPU
1 0180.c200.0009 STATIC CPU
1 0180.c200.000a STATIC CPU
1 0180.c200.000b STATIC CPU
1 0180.c200.000c STATIC CPU
1 0180.c200.000d STATIC CPU
1 0180.c200.000e STATIC CPU
1 0180.c200.000f STATIC CPU
1 0180.c200.0010 STATIC CPU
1 ffff.ffff.ffff STATIC CPU
James
ccie2be wrote:
Hey James,
Let's suppose for a moment, someone taking the lab couldn't remember that
mac address.
How would they find it out? Check the config guide?
Thx, Tim
-----Original Message-----
From: nobody@groupstudy.com [ mailto:nobody@groupstudy.com ] On
Behalf Of
James Ventre
Sent: Thursday, April 21, 2005 11:56 AM
To: ccielab@groupstudy.com Subject: Re: blocking VTP traffic
MAC ACL to block destination of: 01-00-0C-CC-CC-CC ??
But on a lot of platforms MAC ACL's are only for NON IP traffic ... so
be careful.
James
ccie2be wrote:
Pankaj,
I think the only way to do this would be by using a vlan acl.
VTP traffic I believe is always carried in the management vlan which is
vlan
1.
The real issue I think is figuring out how to specify vtp traffic in the
vlan map.
Off-hand, I don't know how to specify vtp traffic but maybe there's a
debug
which could shine some light on this question.
HTH, Tim
-----Original Message-----
From: nobody@groupstudy.com [ mailto:nobody@groupstudy.com ] On Behalf Of
Pankaj Madhukar Kulkarni
Sent: Thursday, April 21, 2005 11:04 AM
To: ccielab@groupstudy.com Subject: blocking VTP traffic
Hi Group,
If the question demands that all "VTP traffic should be blocked". Does
this require that both the switches be configured in the transparent
mode???
Regards,
Pankaj K
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