[c-nsp] BGP conditional advertisemet - NON-EXIST route map'saccess-list problem
Burak Dikici
bdikici at gmail.com
Sun Mar 22 03:46:40 EDT 2009
Hi Randy ,
I couldn't understand what you mean with a local-route ? Could you explain
little more ?
Burak
On Sun, Mar 22, 2009 at 1:09 AM, <RPhookun at lecg.com> wrote:
>
> Hi Burak,
> Ask ISP-A to announce the infrastructure /24 to router# as a local-route
> via a network statement 192.168.x.0 mask 255.255.255.0. They may not want to
> do the same via redistribute-connected(if rtr-ISP-1 is also used for
> peerring with other customers)
>
> ./Randy
>
>
>
> *Burak Dikici <bdikici at gmail.com>*
> Sent by: cisco-nsp-bounces at puck.nether.net
>
> 03/21/2009 03:34 PM
> To
> RPhookun at lecg.com cc
> ip at ioshints.info, cisco-nsp-bounces at puck.nether.net,
> cisco-nsp at puck.nether.net
> Subject
> Re: [c-nsp] BGP conditional advertisemet - NON-EXIST route
> map'saccess-list problem
>
>
>
>
>
> Hi Randy ,
>
> I have missied the point. I am going to talk this subject with the ISP-1.
> Kind Regards.
>
> Burak Dikici
>
>
>
>
> On Sat, Mar 21, 2009 at 8:12 PM, <RPhookun at lecg.com> wrote:
>
> >
> > Hi Burak,
> >
> > I had replied with the *fix* some days ago -
> > You can still use the ISP-1 infrastructrure /24. You have to have the
> ISP-1
> > router announce the /24 to router#
> > As you probably realise, this announcement is not required for the
> peering
> > session *itself* to be up.
> >
> > The annoucement by ISP-1 router of this /24 will cause it to appear in
> > router#'s bgp table which you can then use as the tracked prefix.
> >
> > Router#'s routing table will always install only the *connected*(d-0)
> > version of this /24 which is what you want! The eBGP version(d-20) will
> > exist only in the bgp table as a valid prefix you can track.
> >
> > Hope this helps.
> > ./Randy
> >
> >
> >
> > *Burak Dikici <bdikici at gmail.com>*
> > Sent by: cisco-nsp-bounces at puck.nether.net
> >
> > 03/21/2009 08:19 AM
> > To
> > RPhookun at lecg.com, ip at ioshints.info cc
> > cisco-nsp-bounces at puck.nether.net, cisco-nsp at puck.nether.net
> > Subject
> > Re: [c-nsp] BGP conditional advertisemet - NON-EXIST route
> > map'saccess-list problem
> >
> >
> >
> >
> >
> > Hello ,
> >
> > The main problem is which prefix should i track ? I can't use the
> > infrastructe subnet between my router and ISP-1 router , because it is
> > directly connected and it is in the routing table , not in the bgp table.
> > I was thinking on that , then i have decided to use reliable root DNS
> > servers subnets to track with acl or prefix-list , for example ;
> >
> > access-list 20 permit 198.41.0.0 0.0.0.255 /* a.root-servers.net */
> > access-list 20 permit 192.228.79.0 0.0.0.255 /* b.root-servers.net */
> > access-list 20 permit 192.33.4.0 0.0.0.255 /* c.root-servers.net */
> > access-list 20 permit 128.8.0.0 0.0.255.255 /* d.root-servers.net */
> >
> > what do you think about this idea ?
> >
> > Burak Dikici
> >
> >
> >
> >
> > On Thu, Mar 19, 2009 at 2:48 PM, Burak Dikici <bdikici at gmail.com> wrote:
> >
> > > Sorry about my late reply. I am very busy these days with another
> > project.
> > > I am going to test your recommendations in a few days , and going to
> > reply
> > > back to you. Thank you all. Kind Regards...
> > >
> > > Burak Dikici
> > >
> > >
> > >
> > > On Wed, Mar 18, 2009 at 12:04 AM, <RPhookun at lecg.com> wrote:
> > >
> > >>
> > >> The prefix-list within the Non-Exist clause also has to *exactly*
> match
> > >> the prefix in the bgp table..
> > >> Regards,
> > >> ./Randy
> > >>
> > >>
> > >>
> > >>
> > >> *"Ivan Pepelnjak" <ip at ioshints.info>*
> > >> Sent by: cisco-nsp-bounces at puck.nether.net
> > >>
> > >> 03/17/2009 02:20 PM
> > >> To
> > >> "'Dale Shaw'" <dale.shaw+cisco-nsp at gmail.com<dale.shaw%2Bcisco-nsp at gmail.com>
> <dale.shaw%2Bcisco-nsp at gmail.com <dale.shaw%252Bcisco-nsp at gmail.com>>
> > <dale.shaw%2Bcisco-nsp at gmail.com <dale.shaw%252Bcisco-nsp at gmail.com> <
> dale.shaw%252Bcisco-nsp at gmail.com <dale.shaw%25252Bcisco-nsp at gmail.com>>>>,
>
>
> >
> > >> "'Burak Dikici'" <bdikici at gmail.com> cc
> > >> cisco-nsp at puck.nether.net Subject
> > >> Re: [c-nsp] BGP conditional advertisemet - NON-EXIST route
> > >> map'saccess-list problem
> > >>
> > >>
> > >>
> > >>
> > >>
> > >> Did some tests on the NON-EXIST-MAP with 12.2SRC. I was spreading
> wrong
> > >> rumors, time to fix them:
> > >>
> > >> * The route-map checks the routes in the BGP table (_not_ in the IP
> > >> routing
> > >> table). Dale was right.
> > >> * It can take a while for the routes to be advertised/withdrawn; the
> > >> non-exist-map is checked only at the BGP scan intervals (60 seconds by
> > >> default, can be adjusted).
> > >> * You can use a combination of an access-list and AS-path access-list
> in
> > >> the
> > >> route-map.
> > >>
> > >> The handling of standard access-lists used in the "match ip address"
> > >> route-map condition is a bit weird, though:
> > >>
> > >> * "permit any" does _NOT_ work.
> > >> * "permit prefix 0.0.0.0" (which gets translated into "permit prefix"
> in
> > >> standard ACL) does _NOT_ work.
> > >> * fancy wildcard tests (for example "permit 0.0.0.0 127.255.255.255)
> do
> > >> _NOT_ work
> > >>
> > >> It looks like:
> > >>
> > >> * the IP prefix in the BGP table must match the address in the ACL
> > exactly
> > >> (wildcard bits are ignored).
> > >> * ... but you still need the wildcard bits (inverted netmask) for the
> > >> match
> > >> to work.
> > >>
> > >> For example: if you want to match 10.8.8.0/24, you have to use
> "permit
> > >> 10.8.8.0 0.0.0.255". "permit 10.8.8.0" or "permit 10.8.0.0
> 0.0.255.255"
> > do
> > >> _NOT_ work.
> > >>
> > >> Left to do: tests with the ip prefix-list instead of IP access list
> (and
> > >> no,
> > >> I will NOT test extended ACL :).
> > >>
> > >> Hope this helps
> > >> Ivan
> > >>
> > >> > -----Original Message-----
> > >> > From: Dale Shaw [mailto:dale.shaw+cisco-nsp at gmail.com<dale.shaw%2Bcisco-nsp at gmail.com>
> <dale.shaw%2Bcisco-nsp at gmail.com <dale.shaw%252Bcisco-nsp at gmail.com>>
> > <dale.shaw%2Bcisco-nsp at gmail.com <dale.shaw%252Bcisco-nsp at gmail.com> <
> dale.shaw%252Bcisco-nsp at gmail.com <dale.shaw%25252Bcisco-nsp at gmail.com>>>]
> > >>
> > >> > Sent: Sunday, March 15, 2009 11:33 PM
> > >> > To: Burak Dikici
> > >> > Cc: cisco-nsp at puck.nether.net
> > >> > Subject: Re: [c-nsp] BGP conditional advertisemet - NON-EXIST
> > >> > route map'saccess-list problem
> > >> >
> > >> > Hi Burak,
> > >> >
> > >> > On Mon, Mar 16, 2009 at 12:06 AM, Burak Dikici
> > >> > <bdikici at gmail.com> wrote:
> > >> > > i am trying to use
> > >> > > BGP conditional advertisemet configuration. I have got a
> > >> > problem with
> > >> > > NON-EXIST route map's access-list. In the NON-EXIST router map i
> am
> > >> > > using the commands which is written below ;
> > >> >
> > >> > Here are some notes I made recently when playing with BGP
> > >> > conditional advertising. I hope it helps.
> > >> >
> > >> > 1.) prefixes matched in advertise-map and exist/non-exist map
> > >> > must exist (or not) in the *BGP* table
> > >> > however: they do not need to be locally originated (e.g. R1
> > >> > can match routes received from R2 and advertise (or not) to R3
> > >> > and: the validity of the prefix in the BGP table (i.e.
> > >> > RIB-failure) doesn't matter. if there's there, and using
> > >> > exist-map, the condition is met.
> > >> >
> > >> > 2.) when using 'exist' map, prefixes matched by advertise-map
> > >> > are advertised when exist-map condition is met
> > >> > example: advertise 1.0.0.0/8 (advertise-map) from BGP table when
> > >> > 3.20.20.0/24 (exist-map) exists in BGP table
> > >> >
> > >> > 3.) when exist 'non-exist' map, prefixes matched by
> > >> > advertise-map are advertised when non-exist-map condition is met
> > >> > example: advertise 1.0.0.0/8 (advertise-map) from BGP table when
> > >> > 3.20.20.0/24 (non-exist-map) does NOT exist in BGP table
> > >> >
> > >> > 4.) prefixes matched in advertise-map are the only prefixes
> > >> > affected -- other prefixes that may exist are advertised (or
> > >> > not) as normal
> > >> >
> > >> > 5.) when dealing with conditional advertisement tasks, always
> > >> > consider what will happen normally (without any config)
> > >> >
> > >> > I'd be happy to be corrected, but I think the first point is
> > >> > contrary to what Ivan said. Also consider point #4 -- BGP
> > >> > conditional advertising is not strictly a route filtering
> > >> > mechanism, although it can be configured to achieve similar results.
> > >> >
> > >> > cheers,
> > >> > Dale
> > >> >
> > >> >
> > >>
> > >> _______________________________________________
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> > >>
> > >>
> > >
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> >
> >
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