I suspect many providers don't have good business processes for reclaiming IP space that was assigned to customers who have either disconnected or voluntarily returned the space.
The provider I started out with in the mid/late 90s bootstrapped itself with IP space from MCI (now, CenturyLink... I think?) and UUNET (now Verizon Business), but we handed those blocks back when we started getting provider-independent space from ARIN. No idea what became of that space after we stopped announcing it. jms On Fri, Oct 2, 2020 at 3:38 PM Ryan Wilkins <r...@deadfrog.net> wrote: > I have the same thing with a service that was disconnected a couple years > ago. Four IP blocks of /24 size are still swipped to us and we’re > announcing them. I don’t put any customers on them and just use them for > temporary things for fear that some day someone will want them back. > > On Oct 2, 2020, at 2:50 PM, Matt Brennan <brenna...@gmail.com> wrote: > > > A service I disconnected more than 2 years ago still has a /24 of their > space SWIPED to me. Their NOC closed the ticket I opened to remove. Unknown > if it's actually in use for another customer. > > I also had a conversation last week with another ISP (we were > renegotiating our contract) about this. The order form they sent me had > multiple /28's we had "given back" years ago still listed. Turns out > they're still being routed to us as well. > > I would bet it happens all over the place. > > -Matt > > On Fri, Oct 2, 2020 at 2:00 PM Matt Hoppes < > mattli...@rivervalleyinternet.net> wrote: > >> 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? >> > >