IPv4 Mismanagement

Fri Oct 2 17:58:36 UTC 2020

I'm sitting here in the office on a Friday performing some IP 
maintenance and I see that one of our upstreams is still filtering an IP 
range we haven't used in years.   I dig into it a bit more and it turns 
out a major carrier still has them SWIPed to us.

This got me curious and I dug more into IPs from back in our early days 
and discovered there are two Tier-1 carriers we no longer do business 
with that still have large blocks of their own IPs SWIPED and allocated 
to us.

This is really confusing and concerning.   I know it's not the 
end-all-be-all, but I wonder how much IPv4 exhaustion is being caused by 
this type of IPv4 mis-management, where IPs are still shown as 
"allocated" to a customer who hasn't used them in years.

I've seen this behavior from Frontier and CenturyLink to name just a few.

Any thoughts on this?