Quick question for people who bought IPv4 recently.

[Jonh Newman]

Hey all. Quick question for people who bought IPv4 recently. How do you check a block's reputation before paying? I got an offer for a /24 that looks cheap, and when I searched the range it showed up on a couple of blocklists. The seller says it's all fine and just needs cleaning. I'm not sure whether that's normal. What do you do to verify a block, and do reputable marketplaces handle this for you? I've been burned once by a /24 that was clean on paper but stuffed with spam history. It cost us two months of cleanup and a very angry customer.

[Konstantin Volkov]

A cheap block with blocklist entries usually isn't a bargain. I check the range on several public blocklists, look at its history in routing data, and ask the seller what it was used for before. On the InterLIR IPv4 marketplace the pitch is 'no abuses' and networks from real owners, which is the kind of promise you should ask them to back with details. I'd make delisting a condition of purchase, or walk away. Test the range with a small announcement before you commit. We made the second purchase conditional on a clean result after thirty days, and the seller agreed, which says a lot about who is confident in their stock. Also keep screenshots of the blocklist checks from the day you looked.