How to block a incomplete origin code route in BGP

Unanswered Question
Aug 15th, 2008

Hi Fellow Networkers,

I was trying to block a BGP route with incomplete origin code(?) but got no luck.

i tried route-map but there is no match statement for origin code, i also tried regular expression but still it didn,t work...

Routers are connected in below mentioned fashin.

R1 <---> R2 <---> R3

BGP route is coming from R1 and i am stopping it on R3.

any help really appreciated.

I have this problem too.
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Giuseppe Larosa Fri, 08/15/2008 - 07:55

Hello Mohinder,

? is a special character in reg exp.

try to use \? to say you want match exactly char '?'

Hope to help


mohindersingh Fri, 08/15/2008 - 12:53

Hi Guisiar,

Thanks for the reply.

but how to stop the incomplete route..normally regular expression we use with as-path acccess list. but we have to stop a route with incomplete origin code so we can,t use regular expression.

do you know any method to block origin code with regular expression.


Giuseppe Larosa Fri, 08/15/2008 - 13:23

Hello Mahi,

what you write inside an as path list is actually a regular expression

define an as path list that matches ? at the end of as path


use the as-path access-list inside a route-map

route-map stop-incomplete deny 10

match as-path X

match ip address

route-map stop-incomplete permit 20

empty block to permit all other routes

apply the route-map inbound on R3 on the BGP session with R2 and you should get the result.

Hope to help



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