[ncc-services-wg] Finding previous user of IP addresses

I freely admit to being a bit rusty on these matters, so please indulge 
me.

Now that ipv4 address space is so scarce, but demand continues, I'm 
aware of a public sector organisation who changed ISP, and was 
renumbered with what have apparently turned out to be rather dirty 
addresses.

Such that many blue-chip ecommerce providers have them blacklisted as a 
result of their former life. (Why it takes so long to un-black-list them 
is a separate debate).

My question is this: how can the organisations responsible for that 
former life be identified (in general terms) so that the end users can 
at least given a plausible explanation for why their connectivity has 
been so badly affected.

As far as I know, all the new ISP is prepared to divulge is "we are 
working on it", and all the users' IT departments are prepared to 
divulge is "Our new ISP says he's working on it".

If this isn't the right place to ask, I'm happy to be directed 
elsewhere.
-- 
Roland Perry