RE: Best practices inquiry: filtering 128/1

Would anyone not filter those routes? Why wouldn't you filter to /7?

Actually, I take that back. Why wouldn't you just get a feed from
Cymru <; ??

We had some hesitation on putting in a 1/ le /7 filter as these are not mentioned in any document / recommendation that they are invalid / bogus routes... nor in the Cymru.

Anyway, just spotted this in Cymru [Ingress Prefix Filter Templates, Loose and Strict (Cisco)] but it was not included / mentioned in their fltr-bogons:

! Block Prefixes less than /5.
ip prefix-list ISP-Ingress-In-Loose seq 50 deny le 5
! Block /6 and /7 prefixes - We have this in as a marker to see if any of the
! large networks pull together any /8s into smaller blocks. Watch this hit
! counters with "show ip prefix". Tuned per Adriana Vascan <>
! suggestion.
ip prefix-list ISP-Ingress-In-Loose seq 55 deny le 6
ip prefix-list ISP-Ingress-In-Loose seq 60 deny le 7