Date: Sat, 20 Mar 1999 19:17:33 -0500 From: Craig Metz <cmetz@inner.net> To: Bill Fumerola <billf@chc-chimes.com> Cc: freebsd-net@FreeBSD.ORG Subject: Re: natd and ipmasq Message-ID: <199903210018.AAA00909@inner.net> In-Reply-To: Your message of "Sat, 20 Mar 1999 17:24:03 EST." <Pine.HPP.3.96.990320172028.20465A-100000@hp9000.chc-chimes.com>
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In message <Pine.HPP.3.96.990320172028.20465A-100000@hp9000.chc-chimes.com>, yo u write: >> what's the difference between NATD dan ipmasquerading on LInux ? >> i thought that was the same.. is that true ? > >NAT is the official name that the IETF uses to refer to the concept of >network address translation. FreeBSD and everyone else refers to it as >NAT, while natd is the daemon that performs the translation in FreeBSD. > >IP Masquerading is some silly term that the Linux people came up with to >be different. Though I believe it works the same way as the rest of the >free world's implementation. NAT means "Network Address Translation" which is a 1-to-1 mapping done to make renumbering less painful. Not long after NAT came the x-to-y (e.g., many-to-one) mappings where ports are used to allow "connections" to be mapped rather than just addresses (which is all not so hard to do once you're mucking with transport/application layers to twiddle the addresses), which is done to conserve address space (e.g., when your ISP only gives you one). These are incorrectly also called NAT, but that incorrect usage appears to now be common and in no danger of being corrected. Linux has both NAT and the not-really-NAT mapping modes; the former is called NAT and the latter is called IP Masquerading. Linux's NAT only does the 1-to-1 case and IP Masquerade only does the many-to-one case. Linux's labelling the latter "IP Masquerading" approximately predates the common misuse of the term "NAT" for this purpose. FreeBSD's natd probably does 1-to-1 and many-to-one, which are the two common cases. Both systems do approximately the same things in this problem space. -Craig To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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