Someone posted a response in alt.computer.security and here Wednesday to
a June 2003 posting which reminded me to grab a copy of the latest spysite
list. Looking at it, I see four network masks that are not valid for any
network host I have access to.

http://www.geocities.com/yosponge/blockips.txt

grep 255.255.6 blockips.txt
208.215.64.0 255.255.64.0 DSSAgent (Broderbund/Mattel)
64.12.174.57 255.255.255.63 AOL Advertising ******
205.188.165.57 255.255.255.63 AOL Advertising ******
152.163.208.57 255.255.255.63 AOL Advertising ******

Both 255.255.255.63 and 255.255.64.0 are non-contiguous masks, and are
unlikely to work in a UNIX environment. If you want to trace things out,
RFC0950 does allow for this (as does RFC1122 section 3.2.1.3), but it is
very much frowned upon. See RFC1219, RFC1518, RFC1519, and RFC1878.

0950 Internet Standard Subnetting Procedure. J.C. Mogul, J. Postel.
Aug-01-1985. (Format: TXT=37985 bytes) (Updates RFC0792) (Also
STD0005) (Status: STANDARD)

1122 Requirements for Internet Hosts - Communication Layers. R.
Braden, Ed.. October 1989. (Format: TXT=295992 bytes) (Updated by
RFC1349) (Also STD0003) (Status: STANDARD)

1219 On the assignment of subnet numbers. P.F. Tsuchiya. Apr-01-1991.
(Format: TXT=30609 bytes) (Status: INFORMATIONAL)

1518 An Architecture for IP Address Allocation with CIDR. Y. Rekhter,
T. Li. September 1993. (Format: TXT=72609 bytes) (Status: PROPOSED
STANDARD)

1519 Classless Inter-Domain Routing (CIDR): an Address Assignment and
Aggregation Strategy. V. Fuller, T. Li, J. Yu, K. Varadhan. September
1993. (Format: TXT=59998 bytes) (Obsoletes RFC1338) (Status: PROPOSED
STANDARD)

1878 Variable Length Subnet Table For IPv4. T. Pummill, B. Manning.
December 1995. (Format: TXT=19414 bytes) (Obsoletes RFC1860) (Status:
INFORMATIONAL)

Those documents are available on the web from many different repositories.

The first address/mask (255.255.64.0) seems to translate to 208.215.64.x
through 208.215.127.x and 208.215.192.x through 208.215.255.x, while the
second one would translate to 64.12.174.57, 64.12.174.121, 64.12.174.185,
and 64.12.174.249 (last six bits of each address being 111001). The same
would be true for the third and fourth address listed above. I _really_
don't think that's what was intended.

Old guy