IP Prefix-List Question Part-2

Hi Everyone
how to deny all routes have the first 3-octets 10.100.20 and subnet mask range 24->29 ?

i`ve two solutions to do that

solution#1 ge 25 le 29

solution#2 le 29

but what is the difference between both solutions (solution#1 and solution#2) ge 25 le 29

vs le 29


Hello major133,

Both solutions you wrote will work, but the second solution is the more elegant one.

In reality, if a router sends you a routing update about a prefix, and indicates that the first 24-bits of that prefix are:
00001010 01100100 00010100 (10.100.20)

…then that update will NEVER contain an associated mask anything less than a /24 (otherwise there would be no need to specify all 24-bits in the prefix). So that’s why your second solution is the best one.