From: Carl Phelan (carlphelan@xxxxxxxxxxx)
Date: Sat Mar 30 2002 - 11:23:56 GMT-3
This link answers all:
http://www.cisco.com/warp/public/459/26.html
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Chad Allison
Sent: 29 March 2002 18:44
To: 'ying chang'; bsin@erols.com
Cc: ccielab@groupstudy.com
Subject: RE: AS-path access-list
Guys,
>From what I understood "?" can only be used with netbios reg. exp. Not
as-path filtering.
Comments?
Thanks,
Chad.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
ying chang
Sent: Thursday, March 28, 2002 10:56 PM
To: bsin@erols.com
Cc: ccielab@groupstudy.com
Subject: Re: AS-path access-list
Bob,
I think "_" or " " will give us the same result in this case. Actually,
^701_[0-9]*$, ^701 [0-9]*$, ^701_([0-9]*)?$, or ^701 ([0-9]*)?$ all
returned
the same result when I tried them earlier.
Come to think about it, here is what I think how we get 7018:
"?" is match 0 or 1 occurrences of the pattern. When "?" is equal to 0,
we
will get 701[0-9]*, whether we are using "_" or " ". Baically we got
"^701_[0-9]*$" and "^701[0-9]*$" in our case.
Learn new thing every day.
Thanks,
Chang
>From: "Bob Sinclair" <bsin@erols.com>
>To: "ying chang" <ying_c@hotmail.com>
>CC: <ccielab@groupstudy.com>
>Subject: Re: AS-path access-list
>Date: Thu, 28 Mar 2002 21:47:37 -0500
>
>Ying Chang,
>
>Good catch! ^701 by itself means "starts with 701", and would include
>7010, 7011, 7012, etc. Looks like the underscore is a definite must:
>
>ip prefix-list 1 permit ^701_[0-9]*$
>
>looks like the best way to get AS 701 and its neighbors.
>
>-Bob
>
>
>
>----- Original Message -----
>From: "ying chang" <ying_c@hotmail.com>
>To: <bsin@erols.com>; <tobrien@cinci.rr.com>
>Cc: <ccielab@groupstudy.com>
>Sent: Thursday, March 28, 2002 9:30 PM
>Subject: Re: AS-path access-list
>
>
> > Hi,
> >
> > Can someone explain why sh ip bgp regexp ^701 ?[0-9]*$ pick up 7018?
It
> > looks like sh ip bgp regexp ^701 [0-9]*$ is the only correct way to
do
>it
> > after all.
> >
> > Thanks,
> > Chang
> >
> > route-views.oregon-ix.net>sh ip b regexp ^701_?[0-9]*$
> > BGP table version is 876196, local router ID is 198.32.162.100
> > Status codes: s suppressed, d damped, h history, * valid, > best, i
-
> > internal
> > Origin codes: i - IGP, e - EGP, ? - incomplete
> >
> > Network Next Hop Metric LocPrf Weight Path
> > *> 3.0.0.0 157.130.185.17 0 701 80
i
> > *> 3.18.135.0/24 192.205.31.33 0 7018 ?
> > * 157.130.185.17 0 701
7018 ?
> > * 4.0.0.0 157.130.185.17 0 701 1 i
> > * 6.0.0.0/20 157.130.185.17 0 701
3549 i
> > *> 9.2.0.0/16 157.130.185.17 0 701 i
> > *> 9.184.112.0/20 157.130.185.17 0 701
3786 i
> > *> 9.186.144.0/20 157.130.185.17 0 701
3786 i
> > *> 12.0.0.0 192.205.31.33 0 7018 i
> > * 157.130.185.17 0 701
7018 i
> > * 12.0.252.0/23 157.130.185.17 0 701
16927 i
> > *> 12.3.80.0/22 157.130.185.17 0 701
10998 i
> > *> 12.3.194.0/24 157.130.185.17 0 701
6347 i
> > *> 12.3.217.0/24 157.130.185.17 0 701
16666 i
> > * 12.4.125.0/24 157.130.185.17 0 701
1239 i
> > *> 12.4.126.0/23 157.130.185.17 0 701
17024 i
> > * 12.5.201.0/24 157.130.185.17 0 701
23060 i
> > *> 12.5.202.0/24 157.130.185.17 0 701
22474 i
> > --More--
> >
> > route-views.oregon-ix.net>sh ip b regexp ^701 ?[0-9]*$
> > BGP table version is 876420, local router ID is 198.32.162.100
> > Status codes: s suppressed, d damped, h history, * valid, > best, i
-
> > internal
> > Origin codes: i - IGP, e - EGP, ? - incomplete
> >
> > Network Next Hop Metric LocPrf Weight Path
> > *> 3.0.0.0 157.130.185.17 0 701 80
i
> > *> 3.18.135.0/24 192.205.31.33 0 7018 ?
> > * 157.130.185.17 0 701
7018 ?
> > * 4.0.0.0 157.130.185.17 0 701 1 i
> > * 6.0.0.0/20 157.130.185.17 0 701
3549 i
> > *> 9.2.0.0/16 157.130.185.17 0 701 i
> > *> 9.184.112.0/20 157.130.185.17 0 701
3786 i
> > *> 9.186.144.0/20 157.130.185.17 0 701
3786 i
> > *> 12.0.0.0 192.205.31.33 0 7018 i
> > * 157.130.185.17 0 701
7018 i
> > * 12.0.252.0/23 157.130.185.17 0 701
16927 i
> > *> 12.3.80.0/22 157.130.185.17 0 701
10998 i
> > *> 12.3.194.0/24 157.130.185.17 0 701
6347 i
> > *> 12.3.217.0/24 157.130.185.17 0 701
16666 i
> > * 12.4.125.0/24 157.130.185.17 0 701
1239 i
> > *> 12.4.126.0/23 157.130.185.17 0 701
17024 i
> > * 12.5.201.0/24 157.130.185.17 0 701
23060 i
> > *> 12.5.202.0/24 157.130.185.17 0 701
22474 i
> > --More--
> >
> >
> > >From: "Bob Sinclair" <bsin@erols.com>
> > >Reply-To: "Bob Sinclair" <bsin@erols.com>
> > >To: "Tim O'Brien" <tobrien@cinci.rr.com>
> > >CC: <ccielab@groupstudy.com>
> > >Subject: Re: AS-path access-list
> > >Date: Thu, 28 Mar 2002 20:07:32 -0500
> > >
> > >Tim,
> > >
> > >As you suggested, I did a telnet to:
> > >ner-routes.bbnplanet.net
> > >
> > >and entered:
> > >
> > >ner-routes>sh ip b regexp ^701_[0-9]*$
> > >
> > >Works like a charm, and has the advantage of not having to remember
>Ctl-V
> > >in order to enter the "?"
> > >
> > >Thanks!
> > >
> > >PS: One might also try: http://the.groovy.org/BGP/
> > >for links to mirrors, telnet access.
> > >
> > >----- Original Message -----
> > >From: "Tim O'Brien" <tobrien@cinci.rr.com>
> > >To: "Bob Sinclair" <bsin@erols.com>
> > >Cc: <ccielab@groupstudy.com>
> > >Sent: Thursday, March 28, 2002 7:48 PM
> > >Subject: RE: AS-path access-list
> > >
> > >
> > > > You can test it at ner-routes.bbnplanet.net
> > > >
> > > > Tim
> > > > 9015
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: Bob Sinclair [mailto:bsin@erols.com]
> > > > Sent: Thursday, March 28, 2002 7:43 PM
> > > > To: Tim O'Brien
> > > > Cc: ccielab@groupstudy.com
> > > > Subject: Re: AS-path access-list
> > > >
> > > >
> > > > Tim,
> > > >
> > > > Based on my reading or Halabi, the two statements seem
equivalent:
> > > >
> > > > ip as-path access-list 4 permit ^200_[0-9]*$
> > > >
> > > > and
> > > >
> > > > ip as-path access-list 4 permit ^200 ?[0-9]*$
> > > >
> > > > The underscore can mean most anything, including end of string.
So
>it
> > >would
> > > > match ^200$ to identify routes from the immediate neighbor.
> > > >
> > > > The underscore can also be a space, then [0-9]*$ should match
any
> > >number
> > > > (including zero) of consecutive numerals. Looks to me like both
>would
> > >work.
> > > > The first example may be easier to remember, but I would want to
>test it
> > > > before betting $1,250 on it! I know Halabi's works.
> > > >
> > > > -Bob
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: "Tim O'Brien" <tobrien@cinci.rr.com>
> > > > To: "Bob Sinclair" <bsin@erols.com>; "Hongtu Wang"
> > ><hwang1073@rogers.com>
> > > > Cc: <ccielab@groupstudy.com>
> > > > Sent: Thursday, March 28, 2002 7:29 PM
> > > > Subject: RE: AS-path access-list
> > > >
> > > >
> > > > > I found this one on the Cisco site. What do you think?
> > > > >
> > > > > ip as-path access-list 4 permit ^200_[0-9]*$
> > > > >
> > > > > http://www.cisco.com/warp/public/459/41.shtml#2
> > > > >
> > > > > Tim
> > > > > 9015
> > > > >
> > > > >
> > > > > -----Original Message-----
> > > > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On
>Behalf Of
> > > > > Bob Sinclair
> > > > > Sent: Thursday, March 28, 2002 6:37 PM
> > > > > To: Hongtu Wang
> > > > > Cc: ccielab@groupstudy.com
> > > > > Subject: Re: AS-path access-list
> > > > >
> > > > >
> > > > > Hongtu,
> > > > >
> > > > > I believe you will find that the following expression will
work
>with
> > >the
> > > > > fewest number of statements to define "routes from AS 200 and
its
> > > > > neighbors":
> > > > >
> > > > > ip as-path access-list 4 permit ^200 ?[0-9]*$
> > > > >
> > > > > It is discussed in detail in Halabi's book "Internet Routing
> > > > Architectures",
> > > > > on page 376. The meaning of regular expression characters is
> > >explained on
> > > > > page 187.
> > > > >
> > > > > -Bob
> > > > >
> > > > >
> > > > >
> > > > > ----- Original Message -----
> > > > > From: "Hongtu Wang" <hwang1073@rogers.com>
> > > > > To: <ccielab@groupstudy.com>
> > > > > Sent: Monday, March 25, 2002 10:29 PM
> > > > > Subject: AS-path access-list
> > > > >
> > > > >
> > > > > > Hi,
> > > > > >
> > > > > > My topology is:
> > > > > >
> > > > > > R1(AS100)----R2(AS200)----AS50---AS250
> > > > > >
> > > > > > If I only want to accept routes come from AS200 and all AS
>directly
> > > > > connect to AS200 (AS50 in my topology), how to write as-path
> > >access-list
> > > > on
> > > > > R1?
> > > > > >
> > > > > > Thanks
> > > > > >
> > > > > > Hongtu Wang
> > > > > >
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