09-10-2010 09:35 AM - edited 03-04-2019 09:43 AM
Hi expert,
How can I count the actual IP range of below prefix list
ip prefix-list abc seq 10 deny 10.100.64.0/18 ge 24
ip prefix-list abc seq 20 permit 10.100.0.0/16 ge 24
ip prefix-list abc seq 30 deny 10.100.0.0/14 ge 16
ip prefix-list abc seq 40 deny 10.104.0.0/13 ge 16
ip prefix-list abc seq 50 deny 10.112.0.0/13 ge 16
ip prefix-list abc seq 100 permit 0.0.0.0/0 le 32
09-10-2010 12:19 PM
Not sure what your question is.
You have a list of prefix lists each one with different instructions.
You want to know which IP ranges are matched by the permit statements? Please clarify.
Federico.
09-10-2010 09:38 PM
Yes, you are right
Thank you!
09-12-2010 12:10 PM
Hi,
ip prefix-list abc seq 10 deny 10.100.64.0/18 ge 24 is matching any prefix within 10.100.64.0/18 (=10.100.64.0 - 10.100.127.255) but the prefix mask length must be greater or equal /24. Which means 10.100.66.0/24 is matched, but 10.100.66.0/23 is not, e.g.
The deny keyword is inverting the prefix acceptance logic though, i.e., the matching prefixes are being dropped by the router.
ip prefix-list abc seq 20 permit 10.100.0.0/16 ge 24 is matching any prefix within 10.100.0.0/16 (=10.100.0.0 - 10.100.255.255) but the prefix mask length must be greater or equal /24.
For
ip prefix-list abc seq 30 deny 10.100.0.0/14 ge 16
ip prefix-list abc seq 40 deny 10.104.0.0/13 ge 16
ip prefix-list abc seq 50 deny 10.112.0.0/13 ge 16
the logic is similar to the first line.
ip prefix-list abc seq 100 permit 0.0.0.0/0 le 32 is matching any prefix.
BR,
Milan
09-12-2010 08:38 PM
Hi ,
For ip prefix-list abc seq 10 deny 10.100.64.0/18 ge 24, is it means that
Within the IP range 10.100.64.0 - 10.100.127.255
if route is 10.100.64.0 /24, then is match and will be dropped
if route is 10.100.65.0/ 24, then is match and will be dropped
if route is 10.100.67.0/ 26, then is match and will be dropped
if route is 10.100.64.0/ 22, then is not match and will not dropped
if route is 10.100.72.0/ 22, then is not match and will not dropped
09-12-2010 09:59 PM
Hi,
yes, correct.
This line does not match it.
The final dropping/accepting depends on the following prefix-list lines finally.
BR,
Milan
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: