prefix list !! help plz

[shaila_rox]

hi every1, plz some 1 solve this problem

suppose i have 10 contigiuous networks connected on my routers loopback interfaces

10.1.0.1/16

10.2.0.1/16

10.3.0.1/16

10.4.0.1/16

10.5.0.1/16

10.6.0.1/16

10.7.0.1/16

10.8.0.1/16

10.9.0.1/16

10.10.0.1/16

now i want to advertise only network 10.1.0.0 - 10.4.0.0/16 using prefix list, can some 1 tell me is it possible like i know how to do it in access-list but not getting it in prefix, plz tell me wat will be the prefix list for this???

[Harold Ritter]

You are correct about the nearest 2^n boundary and the fact that you have to add additional statements for prefixes that don't share that common boundary.

It would be a logical XOR for both the prefix part and the mask part though.

Hope this helps,

[nikhil.engineer]

sir I have modified ur acl a bit. do let me know if this is correct.

access-list 101 deny ip 10.0.0.0 0.0.255.255 host 255.255.0.0 /* denies 10.0.0.0/16 from the following block */

access-list 101 permit ip 10.0.0.0 0.7.255.255 host 255.255.0.0 /* permits 10.0.0.0/16 to 10.7.0.0/16 */

access-list 101 permit ip 10.8.0.0 0.2.255.255 host 255.255.0.0 /* permits 10.8.0.0/16 to 10.10.0.0/16 */

Cheers,

Nikhil

[Harold Ritter]

Nikhil,

The last line of the ACL would allow 10.8.0.0/16 and 10.10.0.0/16 but not 10.9.0.0/16 and therefore doesn't meet the requirements.

Hope this helps,