"A number of Register readers have written to us pointing out
that using nslookup, or other similar tools, it's possible to see a
number of servers in the akadns.com [Akamai] domain are listed as
authoritative DNS servers for Microsoft's domains. ... One
enterprising reader used a program called Queso, which
identifies an operating system by the way it constructs IP packets,
which suggests the z*msft.akadns.com domain servers are running
Linux, and identifies use of the 2.1 kernel."
"Matt Power, of security firm BindView Corporation,
said a traceroute on the z*msft.akadns.com reveals that they are
geographically dispersed. However he is less sure than other
readers that the Akamai servers are running Linux."
"He said the Akamai server are running an operating system with
an IP networking implementation similar to that of Linux, which may
or may not be Linux - but is certainly not Microsoft Windows."