If this was a botnot, any one ISP is only seeing a tiny fraction of the load.<p>Even if it were from a single source, it also isn&#x27;t that hard to find an ISP that doesn&#x27;t care. (They cost slightly more, but if you&#x27;re a bad actor, presumably it is worth it.)<p>Edit:<p>&quot;I think pretty much any ISP wouldn&#x27;t let such packets through&quot;<p>If you google &quot;BCP38&quot;, you will find well over a decade of network operators discussing specifically this topic and the reasons why ISPs (and other networks) don&#x27;t, not to mention all the fun the kvetching and meta-kvetching that accompanies any technical discussion that&#x27;s lasted so long.