IPv6 Will Worsen the Spam and Malware Problems

A very high percentage of the sites blocked by your security software for spam or malware are blocked on the basis of the reputation of the IP address on which they reside.

A number of reputation services (Spamhaus, Phishtank, Google Safe Browsing API) provide information on whether sites are trustworthy.

But John Levine, an architect of many Internet e-mail standards and author of The Internet For Dummies, points out that likely ISP practices for IPv6 will make these services useless.

The entire IPv4 address space is 32 bits long and we're running out of addresses. The IPv6 address space is 128 bits which is a lot more than 4 times as big. It's an unimaginably large number.

It's likely that ISPs will allocate to each customer a "/64", meaning a 64-bit address space, giving each user their own insanely large address space of genuine IPv6 addresses. Because of this, spammers and malware authors can simply cycle through all their address periodically, defeating the blacklist. Levine: "...if you sent a billion messages a second, each with its own address, it would take about a thousand years to use all the addresses in a /64."

The good news, which is also the bad news, is that the day when we actually rely on IPv6 addresses seems far away still, even though we will have need of them fairly soon.

blog comments powered by Disqus