Jeffrey, Thanks. A good start, but under-scoped. When you are purchasing IP number blocks whatever source you use; a marketplace, a broker, a single source should provide you with a compelling history on a number block REPUTATION that includes all the attributes listed below and then some. Some of the blocks I’ve seen being discussed lately appear notorious. In one case I counted 17 difffernt RBL’s being attributed to it. Checking Spamhaus is good, but then there are many others and some not so well known. There are many embedded in devices (remember auto config) that will never be updated. For most, do not buy v4 numbers blocks without a pro and you’ll sorta know when they talk about everything but price. Price matters, but if its unusable or you need to spend a month cleaning it up, no income = more cost. Best, -M< On Wed, Apr 3, 2019 at 15:38 Jeffrey Hathaway via NANOG <nanog@nanog.org> wrote:
Hi,
While I think #3 is important, it depends on your use of the end-block, and those entries can sometimes be cleaned up with some work. If the block is listed, that would certainly lower my buying price I am willing to pay for the block. I did buy a block once in the ARIN region which showed up in IP geolocation databases as Russian (no idea why), but it took me quite a while to get it fixed.
*Sincerely,*
*Jeffrey Hathaway*
Information Technology • Howard Center Inc.
*From:* NANOG <nanog-bounces@nanog.org> *On Behalf Of *Torres, Matt via NANOG *Sent:* Wednesday, April 3, 2019 11:20 AM *To:* nanog@nanog.org *Subject:* Purchasing IPv4 space - due diligence homework
All,
Side stepping a migration to IPv6 debate…. I’d like to hear advise from the group about performing due diligence research on an IPv4 block before purchasing it on the secondary market (on behalf of an end-user company). My research has branched into two questions: a) What ‘checks’ should I perform?, and b) what results from those checks should cause us to walk away?
My current list is:
1. Check BGP looking glass for route. It should not show up in the Internet routing table. If it does, walk away. 2. Check the ARIN registry. The longer history without recent transfers or changes is better. I don’t know what explicit results should cause me to walk away here. 3. Check SORBS blacklisting. It should not show up except maybe the DUHL list(?). If it does, walk away.
Anything else? Advise?
Thanks,
Matt
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