Reverse or inverse ARP from windows/linux - no way (!?!?)
in [Design]
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From: Didi on 30 Mar 2010 01:46 On Mar 30, 7:15 am, "JosephKK"<quiettechb...(a)yahoo.com> wrote: > On Tue, 30 Mar 2010 00:44:16 +0200, Hans-Bernhard Bröker <HBBroe...(a)t-online.de> wrote: > >Didi wrote: > > >> I tried today to figure out a simple way to give users of our > >> new netmca (http://tgi-sci.com/tgi/nmcatb.htm) to locate its > >> IP address once it gets one via dhcp when there is no internet > >> at the moment > > >I believe that, strictly speaking, that can't happen. If you have no > >internet at the moment, you don't have DHCP either. Remember that DHCP > >itself is a UDP service. UDP in turn works on top of IP, and that, for > >better or for worse, is "internet". > > No. UDP does not use IP all. It operates in parallel with IP, and provides > a different service. Al least that is what the RFCs say. You are aware that UDP is IP encapsulated, just like tcp? If tcp is one level above IP then UDP also is. But like I said, I am not particularly interested in that sort of "official" side of things. dhcp is indeed running over UDP, but during the gray period of network setup; then at least the request is broadcast etc., some level cheating is applied during the process. Dimiter ------------------------------------------------------ Dimiter Popoff Transgalactic Instruments http://www.tgi-sci.com ------------------------------------------------------ http://www.flickr.com/photos/didi_tgi/sets/72157600228621276/
From: glen herrmannsfeldt on 30 Mar 2010 03:19 In comp.protocols.tcp-ip Didi <dp(a)tgi-sci.com> wrote: (snip) > There are DHCP servers in the absence of internet. For example, a > popular type of cable models do assign IP addresses of the > 192.168.... kind when it has no link over the TV cable. > Routers do that whether they are linked to the internet or not. > On which planet do you live. There is internet, and there is the Internet. You can have a network, even an internet (network of networks) not connected to the Internet (the rest of the world). Any of them may or may not have a DHCP server on them. -- glen
From: Anne & Lynn Wheeler on 30 Mar 2010 10:55 "JosephKK"<quiettechblue(a)yahoo.com> writes: > First off the TCP/IP stack is 4 levels, and the ISO model is 7 layers. > Thus there is intrinsic mismatch. Much of the TCP/IP model tools span > two or more layers in the ISO model. The real deal for TCP/IP protocol > definitions comes from the IETF RFC library. > > http://www.ietf.org/rfc.html > > Please note that this RFC information is freely available for any use. note quite true anymore ... the copyright notice use to say that author gives unlimited rights including any derivative works as long as the IETF copyright notice was included. A couple years ago, that was changed .... and now it ways that RFC authors may retain rights (so RFCs published since the change are subject to the new copyright rules). look at RFCs related to IETF Trust ... for instance 5377 5377 I Advice to the Trustees of the IETF Trust on Rights to Be Granted in IETF Documents, Halpern J., 2008/11/10 (8pp) (.txt=17843) (See Also 5378) (Refs 3935, 4071, 4371) (Ref'ed By 5744, 5745) current documents carry the following This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document .... i got hit with it and had to hire a copyright lawyer out of my own pocket (situation where an attempt was made to try and apply the new rules to RFCs published under the old rules) ... and suggested that they needed to make it much more clear to the authors about copyright changes. -- 42yrs virtualization experience (since Jan68), online at home since Mar1970
From: Rick Jones on 30 Mar 2010 14:00 In comp.protocols.tcp-ip JosephKK <quiettechblue(a)yahoo.com> wrote: > First off the TCP/IP stack is 4 levels, and the ISO model is 7 > layers. Thus there is intrinsic mismatch. Much of the TCP/IP model > tools span two or more layers in the ISO model. The real deal for > TCP/IP protocol definitions comes from the IETF RFC library. The ISO and the IETF are both wrong. There are nine layers :) https://www.isc.org/files/9layer.thumb.png rick jones -- firebug n, the idiot who tosses a lit cigarette out his car window these opinions are mine, all mine; HP might not want them anyway... :) feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
From: glen herrmannsfeldt on 30 Mar 2010 16:11
In comp.protocols.tcp-ip Rick Jones <rick.jones2(a)hp.com> wrote: (snip) > The ISO and the IETF are both wrong. There are nine layers :) > https://www.isc.org/files/9layer.thumb.png The story I still remember is that between Europe and US one wanted six and one eight (I don't remember which) so they compromised on seven. Also, for ATM, one wanted 32 byte payload, one 64, so they compromised on 48. (I would have thought it would be geometric mean, though.) -- glen |