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<p class="MsoNormal">Thanks NANOG. For those interested, here is a summary list of due diligence tasks for purchasing IPv4 on the secondary market:<o:p></o:p></p>
<ol style="margin-top:0in" start="1" type="1">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">Check out the seller (Google search). What is their story? Generally avoid hosting companies because they may have more block/black list cleanup to do.
<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">Check the BGP looking glass Internet routing table. Make sure the IPv4 address is not routed right now.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">Check the historical Internet routing table. It is a good sign if the IPv4 network was advertised from the right company/ASN without recent changes
<span class="MsoHyperlink"><a href="https://stat.ripe.net/widget/routing-history#">https://stat.ripe.net/widget/routing-history#</a></span><o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">Check ARIN registration. Singular, long standing registration for the IPv4 space is a good sign.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">Check block list / black list. SORBS and Spamhaus are good resources. It is a good sign if the IPv4 network does not show up at all.
<span class="MsoHyperlink"><a href="http://www.anti-abuse.org/multi-rbl-check/">http://www.anti-abuse.org/multi-rbl-check/</a></span><o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">Check geo-location. It is a good sign if the IPv4 space shows up in the right global region. Try MaxMind.<o:p></o:p></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1">There is a PowerShell script (that can be expanded on) to help expedite the checking process.
<span class="MsoHyperlink"><a href="https://www.saotn.org/powershell-blacklist-check-script/#more-2459">https://www.saotn.org/powershell-blacklist-check-script/#more-2459</a></span><o:p></o:p></li></ol>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Matt<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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