Martian and RFC1918 addresses

rfuller at rfuller at
Thu Jul 29 22:56:00 UTC 1999

I have been reading Cisco's "Essential IOS Features Every ISP Should
Consider" document and came across a section called Martian and RFC1918
networks.  It is discussing different bogus or reserved networks that
should be filtered by every ISP.  In the list are some addresses I thought
were legal and after checking the ARIN Whois database, some of them seem to
be.  Can anyone give me some additional information as to the need to
filter the following networks:             reserved for IANA          this belongs to Ford            reserved for IANA         this belongs to SUN         IANA use for local link numbers???      reserved for IANA      no ARIN match         no ARIN match          this belongs to SUN

If you can elaborate on what they are used for and if any problems would
arise from filtering these networks, it would be appreciated.  If you could
also please include where you found the information, I would appreciate it.
Some of them belong to companies, so why would you filter them?  Are they
development networks for Ford and SUN?  Are there any other martian
networks that should be filtered?

Here is the URL for the doc if anyone is interested:

Thanks in advance!

3X Corporaton
rfuller at

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