From: Jason Sinclair (sinclairj@powertel.com.au)
Date: Sun Oct 27 2002 - 19:27:28 GMT-3
HK,
You are correct - again it comes to terminology and topology. In the lab if
they wanted routes ORIGINATING from the CONNECTED AS you would use ^$, if
not then you would have to use _$ as you would not know if they were
connected or not.
Regards,
Jason Sinclair CCIE #9100
Manager, Network Control Centre
POWERTEL
55 Clarence Street,
SYDNEY NSW 2000
AUSTRALIA
office: + 61 2 8264 3820
mobile: + 61 416 105 858
email: sinclairj@powertel.com.au
-----Original Message-----
From: Hamele Kassa [mailto:hkassa@attrmc.net]
Sent: Friday, 25 October 2002 22:50
To: Jason Sinclair; ccna instructor
Cc: ccielab@groupstudy.com
Subject: Re: BGP as-path filter
Jason,
My understanding is you use "^" if the originating AS directly connected AS
and use "_" if there could be other AS's in the path. Let's say the
originating AS is 777, then
^777$ means directly from 777 however
_777$ could be the following
777
100 777
200 100 777
200 300 400 777 etc meaning it originated from xxx but could also be other
AS in the path.
Am I missing the point.
Rgs,
HK
----- Original Message -----
From: "Jason Sinclair" <sinclairj@powertel.com.au>
To: "'Hamele Kassa'" <hkassa@attrmc.net>; "ccna instructor"
<ccna20877@yahoo.com>; <ccielab@groupstudy.com>
Sent: Thursday, October 24, 2002 9:04 PM
Subject: RE: BGP as-path filter
> The reason I used the anchors ^ and $ was that the question stated "to
allow
> routes originated from the following ASNs....". This is an important part
of
> the lab exam - understanding the question. In this case it was explicitly
> stated "originated from", hence the correct answer would have to be:
>
> Ip as-path access-list 1 permit ^123$
> Ip as-path access-list 1 permit ^234$
> Ip as-path access-list 1 permit ^345$
> Ip as-path access-list 1 permit ^567$
> Ip as-path access-list 1 permit ^678$
> Ip as-path access-list 1 permit ^990$
> Ip as-path access-list 1 permit ^2345$
> Ip as-path access-list 1 deny .*
>
> That said, there may be a case where the paths are prepended with the same
> AS, in which cas you would have to allow multiple occurrences of the same
> AS.
>
> Cheers,
>
> Jason Sinclair CCIE #9100
> Manager, Network Control Centre
> POWERTEL
> 55 Clarence Street,
> SYDNEY NSW 2000
> AUSTRALIA
> office: + 61 2 8264 3820
> mobile: + 61 416 105 858
> email: sinclairj@powertel.com.au
>
> -----Original Message-----
> From: Hamele Kassa [mailto:hkassa@attrmc.net]
> Sent: Friday, 25 October 2002 09:37
> To: ccna instructor; ccielab@groupstudy.com
> Subject: Re: BGP as-path filter
>
> Try this if all the originating AS's is the BGP neighbor router
>
> Ip as-path access-list 1 permit ^123$
> Ip as-path access-list 1 permit ^234$
> Ip as-path access-list 1 permit ^345$
> Ip as-path access-list 1 permit ^567$
> Ip as-path access-list 1 permit ^678$
> Ip as-path access-list 1 permit ^990$
> Ip as-path access-list 1 permit ^2345$
> Ip as-path access-list 1 deny .*
>
> or if not
>
> Ip as-path access-list 1 permit _123$
> Ip as-path access-list 1 permit _234$
> Ip as-path access-list 1 permit _345$
> Ip as-path access-list 1 permit _567$
> Ip as-path access-list 1 permit _678$
> Ip as-path access-list 1 permit _990$
> Ip as-path access-list 1 permit _2345$
> Ip as-path access-list 1 deny .*
>
> ----- Original Message -----
> From: "ccna instructor" <ccna20877@yahoo.com>
> To: <ccielab@groupstudy.com>
> Cc: <sadiq.sadiq@intelsat.com>
> Sent: Wednesday, October 23, 2002 11:11 PM
> Subject: BGP as-path filter
>
>
> > Need a AS-Path filter that is going to allow routes originated from
> > following ASNs
> > 123, 234, 345, 567, 678, 990, 2345
> >
> > Any help appreciated
> > regards
> > sadiq
> >
> >
> >
> >
> > ---------------------------------
> > Do you Yahoo!?
> > Y! Web Hosting - Let the expert host your web site
>
>
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