Community List Verification

From: Michael Wong (Michael.Wong@xxxxxxxxxx)
Date: Thu Sep 06 2001 - 23:59:43 GMT-3


   
Hi Group

I would just like some verification on how community-lists operate when matchin
g multiple community values. This in reference to Doyle Vol II p.282

Here is a community list matching 2 community values which I am using.

   - ip community-list 1 permit 100:2000 2000:100

I have 3 routes on that router. One route has 100:2000 2000:100 and the other 2
 routes have only 2000:100 as you can see below.

p2r5#sh ip bgp 10.2.1.0
BGP routing table entry for 10.2.1.0/24, version 3
Paths: (1 available, best #1, table Default-IP-Routing-Table)
  Advertised to peer-groups:
     CLIENTS
  2000
    10.1.255.8 from 10.1.255.8 (10.1.255.8)
      Origin IGP, metric 0, localpref 100, valid, internal, best
      Community: 2000:100

p2r5#sh ip bgp 10.2.2.0
BGP routing table entry for 10.2.2.0/24, version 2
Paths: (1 available, best #1, table Default-IP-Routing-Table)
  Advertised to peer-groups:
     CLIENTS
  2000
    10.1.255.8 from 10.1.255.8 (10.1.255.8)
      Origin IGP, metric 0, localpref 100, valid, internal, best
      Community: 100:2000 2000:100

p2r5#sh ip bgp 10.2.3.0
BGP routing table entry for 10.2.3.0/24, version 4
Paths: (1 available, best #1, table Default-IP-Routing-Table)
  Advertised to peer-groups:
     CLIENTS
  2000
    10.1.255.8 from 10.1.255.8 (10.1.255.8)
      Origin IGP, metric 0, localpref 100, valid, internal, best
      Community: 2000:100

The book states that when using the community-list to match multiple values, th
e community-list (as shown above) will match either or both. If you want to mat
ch both, you have to use exact-match. However, this where I get stuck ...... lo
ok at the following outputs below .....

p2r5#sh ip bgp community-list 1
BGP table version is 14, local router ID is 10.1.255.1
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
*>i10.2.2.0/24 10.1.255.8 0 100 0 2000 i

p2r5#sh ip bgp community-list 1 exact-match
BGP table version is 14, local router ID is 10.1.255.1
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
*>i10.2.2.0/24 10.1.255.8 0 100 0 2000 i

As you can see, whether I use the "exact-match" command or not, it still matche
s on both values .... not according to the book.

Has anyone else experienced this ????

Thanks ..... MW
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