dns and software, was Re: Reliable Cloud host ?

George Herbert george.herbert at gmail.com
Tue Feb 28 01:12:13 UTC 2012

On Mon, Feb 27, 2012 at 4:59 PM, William Herrin <bill at herrin.us> wrote:
> ....
> Yes, well, that's why we're still using a layer 4 protocol (TCP) that
> can't dynamically rebind to the protocol level below (IP).

This is somewhat irritating, but on the scale of 0 (all is well) to 10
(you want me to do WHAT with DHCPv6???)  this is about a 2.

The application can re-connect from the TCP layer if something wiggy
happens to the layer below.  This is an application layer solution, is
well established, and works fine.  One just has to notice something's
amiss and retry connection rather than abort the application.

> God help us
> when folks start overriding the ethernet MAC address to force machines
> to keep the same IPv6 address that's been hardcoded somewhere or is
> otherwise too much trouble to change.

It could be worse.  Back in the day I worked for a company that did
one of the earlier two-on-motherboard ethernet chip servers.  The Boot
PROM (from another vendor) had no clue about multiple ethernet
interfaces.  It came up with both interfaces set to the same NVRAM-set
MAC.  We wanted to fix it in firmware but kept having issues with

I had to get an init script to rotate the MAC for the second interface
up one, and ensure that it was in the OS and run before the interfaces
got plumbed, get it bundled into the OS distribution, and ensure that
factory MACs were only set to even numbers to start with.

One of these steps ultimately failed rather spectacularly.

-george william herbert
george.herbert at gmail.com

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