2010-01-05 10:38:34 - Amsterdam. It is predicted that by 2012, or sooner, we will not have any IPv4 addresses available anymore. Due to this IP address exhaustion, the Internet Protocol version 4 (IPv4) will be slowly replaced by the next generation, version 6 (IPv6). Since anti-spam measures highly depend on IP reputation checks, the question arises how IPv6 will affect your email inbox.

The difference between IPv4 and IPv6 is very small. IPv6 is simply a different format of characters which results in so many different possibilities for the composition of IP addresses, that it should take centuries before we run out again. “Many anti spam systems focus on the reputation of the sender by evaluating the historical traffic from an IP address. With IPv6 however, there are so many different IP addresses that filtering at this level will not be possible anymore. The blacklists, as we know them right now, will disappear, and whitelists will become a lot more popular”, according to Dreas van Donselaar from the Dutch email-security company SpamExperts.

SpamExperts is cooperating with several Dutch ISPs to establish an obligatory

'IPv6 mail server registration whitelist'. Mr. van Donselaar also indicated that: “Besides whitelisting, it is very important to have accurate email content filtering to avoid dependency on IP reputation. We have developed a special SpamFeed product that will help other anti-spam companies to improve their content scanning technologies”. Although IPv6 may still seem far away, it is approaching quickly and will have serious consequences for everyone that is not ready for it.

What is IPv6 exactly? Instead of the IPv4 composition of an IP address constructed out of 4 sets of numbers, which allows us to create 4 billion different combinations, 8 sets of characters are used for IPv6 instead. This is offering virtually an unlimited amount of different combinations. However, not everybody is that enthusiastic about IPv6. Partly because of the economical crisis, companies seem to postpone the implementation of IPv6 since they are afraid of high implementation costs.