Hi,
Thanks guys for so much interest shown in solving my difficulty.
I did configure similar routers in gns3 and configured. And it worked.
Here is how I am trying to remember the login particularly for BGP route filtering.
on router 1
show ip bgp
10.10.1.0 / 30 ( 10.10.1.0 255.255.255.252)
10.10.1.0 / 29 ( 10.10.1.0 255.255.255.248)
If I want to block ONLY 10.10.1.0 /30 from appearing in bgp routes
Here is my logic it may be terribly wrong !!
exact prefix is : 10.10.1.0 how do we match these exactly :
in binary it is
0000 1010 . 00001010 . 0000 0001 . 0000 00000 to match exact this bit pattern we need mask of all zero : 00000000.00000000.0000000.00000000.
similarly if we need to match / 30 mask we need following pattern
255.255.255.255.252 in binary is
1111 1111 . 1111 1111. 1111 1111. 1111 1100 to match this we need all zero 00000000.00000000.0000000.00000000
( still syntax logic for source address and destination address is not clear for--> how it applies to this BGP filtering case )
so to exactly match :
we had
access-list 101 permit ip 10.10.1.0 0.0.0.0 255.255.255.252 0.0.0.0 or in other words
access-list 101 permit ip host 10.10.1.0 host 255.255.255.252.0
Prefix list : 10.10.1.0 / 30
10.10.1.0 --> is source subnet which you need to match exactly ( 10.10.1.0 0.0.0.0 )
/30 --> Target or destination subnet : match exactly : 255.255.255.252 0.0.0.0 )
For the time being it is clear to me but quite possible I will forget it and even may trigger another good thread.
I need to read prefix-list may a while till i digest all this thread replies !!
Thanks all you friends for all your help.
Subodh
