Vista will make the Net slow and gooey. So says Paul Mockapetris, who invented the Internet’s Domain Name System, in an interview with CNet. According to Mockapetris, Vista’s adoption of IPv6 will double DNS traffic leading to brownouts and shutdowns because DNS servers are already running close to capacity.

This is because the current IPv4 protocol used to stream data packets, was designed primarily for ethernet. It doesn’t guarantee delivery or prevent duplication of data and it is only able to address a little over 4 billion unique addresses. It may sound a lot but is soon whittled down because many are reserved: 18 million for private networks, 1 million for multicasting and so on. Then there are the huge numbers of computers, cell phones and devices all needing their own individual address. Basically, IPv4 has run out of numbers so IPv6 has been devised.

NAT, network address translation, has helped to keep IPv4 running. In the early days of Broadband in the UK, BT supplied every ADSL set-up with 5 unique IP addresses, actually 7 because the first and last were reserved. Nowadays, DHCP, the dynamic host configuration protocol, is more usually supplied with at most 1 static IP address for the DHCP router which allocates a private IP address for each device on it’s internal network, sending data to the correct one using NAT.

This is all very good until computers need end to end connections to run web or FTP servers, or use UDP to send small datagrams to each other. As any on-line gamer can tell, it was often better in the old days when games were played modem to modem rather than across Internet links, with varying ping times.

IPv6 increases the number of addresses to a total that literally words cannot describe, except to say that everyone alive in the world today could have 50 octillion each. The problem is that most DNS servers aren’t using IPv6 even though the US government has specified they must by 2008. Mockapetris thinks that when Vista is introduced the DNS servers will be hit by double the amount of traffic as Vista first checks which protocol to use before putting through its request in the correct format.

Not all industry pundits agree with this, saying that while traffic will be higher, it isn’t going to crash the ‘Net. Microsoft’s view is that Vista will only query DNS servers twice when necessary. If the server isn’t capable of IPv6 it won’t respond.

However, for those of us who run modern operating systems (hum hum) that have been capable of IPv6 for some years this has not necessarily been so. Until fairly recently, when more servers became IPv6 capable, DNS look-ups could cause a big slow down in connectivity as Mac OS X first questioned the server for IPV6 before dropping back to IPv4 once the IPv6 request times out. It also explains mysterious dropped connections from a server that cannot support IPv6 when PHP or other server-side applications only know how to deal with IPv4 addresses. Turning off IPv6 was often the cure for network slowdowns. We even ran our own DNS server in-house for a while. Not as difficult as you would think, or not under OS X anyway.

As Vista is due any day now, err… early next year…whenever. We won’t have long to wait to see if Mockapetris is right.