The RFC 1918 address are not supposed to be routed on the Internet. Within a network, you can do what ever you want with them.
So an ISP that adopts 10. addressing among it's users may (doesn't have to) route the 10. block among it's users. That is, customer one could be assigned 10.1.x.y and customer two assigned 10.2.a.b and it's totally unspecified if these two can see each other. Or the only way they can see each other is through their publicly exposed addresses. NB: As the term was used back then, the capital I internet is what we today call "the [iI]nternet" or the "[pP]ublic [iI]nternet". In older documents, you will occasionally find small i internet references, meaning a network that inter-connects networks. Today we call those LANs or MANs etc. and use "internet" to mean "Internet". -----Burton -----Original Message----- From: Andrew Blevins [mailto:[EMAIL PROTECTED]] Sent: Friday, October 26, 2001 5:02 PM To: 'scott [gts]'; security-basics Subject: RE: help - can someone explain this to me? That these reserved addresses can't be routed I don't think is entirely true (but I'm not a network spec. either! :-) . I have seen many ISP's use 10. addresses for their own routers, and for all intent's and purposes "The Internet" includes some ISP networks (cable, DSL). It is very possible that someone is spoofing those 10. addresses, and they are still being routed through to your box. many times a DoS contains many spoofed source addresses. Andrew Blevins Arrowhead Help Desk 1-800-669-1889 x. 8569
