I have the following prefixes i would like to block 203.4.4.33/27 and 203.4.5.65/26 and allow all the rest what is the correct answer for this?
i have ip prefix-list PFL-1 deny 203.4.4.0/23 ge 26 le 27
ip prefix-list PFL-1 allow 0.0.0.0/0 le 32
is this correct?
Your answer is correct. I configured the networks using loopbacks. You have to change the ospf network type to point-to-point to advertise the correct mask instead of a /32 host route. You also have to configure the prefix-list on the ABR. You can only filter on the ABR.
ip prefix-list PFL-1 deny 203.4.4.0/23 ge 26 le 27
ip prefix-list PFL-1 permit 0.0.0.0/0 le 32
ip prefix-list PL-1 deny 203.4.4.33/27 >>>Deny
ip prefix-list PL-1 deny 203.4.5.65/26 >>>Deny
ip prefix-list PL-1 allow 0.0.0.0/0 le 32 >>>> Permit rest