Reverse or inverse ARP from windows/linux - no way (!?!?)
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From: JosephKK on 1 Apr 2010 00:09 On Wed, 31 Mar 2010 00:31:23 +0200, Hans-Bernhard Bröker <HBBroeker(a)t-online.de> wrote: >Didi wrote: >> On Mar 30, 1:44 am, 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". This erroneous statement alone shows that you are ill prepared to participate in this discussion. If you think UDP "sits" on top of IP you are very mistaken. It is a parallel (at the same level) link/transport protocol. Moreover, you desired email reply shows arrogant disregard for USENET norms. > > > There are DHCP servers in the absence of internet. > >That's only true for a meaning of the term "internet" that IMHO rather >strictly contradicts with your self-proclaimed expertise in internet >technologies. What exactly did the 'I' in IP mean again? > <Snip>
From: JosephKK on 1 Apr 2010 00:16 On Mon, 29 Mar 2010 21:59:52 -0700 (PDT), "robertwessel2(a)yahoo.com" <robertwessel2(a)yahoo.com> wrote: >On Mar 29, 11:15 pm, "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. > > >UDP (and TCP) both use IP as their lower layer. UDP operate in >parallel with *TCP* and provides a different service. They *both* run >over IP. > >It is most emphatically *not* what the RFCs say. In fact, the opening >paragraph of RFC786 (which defines UDP) is: > >"This User Datagram Protocol (UDP) is defined to make >available a >datagram mode of packet-switched computer communication in >the >environment of an interconnected set of computer networks. >This >protocol assumes that the Internet Protocol (IP) [1] is used as >the >underlying protocol." > >And the prior poster is correct - it's IP that basically defines the >Internet - the whole Internet exists to move IP packets around, and >protocols like ICMP, UDP and TCP are built on top of IP. A number of >other less common protocols also are built directly on top of IP >(rather than on top of UDP or TCP). For example, the communication >between routers running OSPF happens over IP, but uses protocol #89, >which is distinct from TCP (6), UDP (17) and ICMP (1). > >As for DHCP, it does, in fact, use a UDP packet, although in many >implementations that's more a formality and the IP header is largely >faked during initial system startup. Having it an actual UDP packet >makes it rather easier for the (DHCP) servers and the rest of the >network, though. Damn, it seems i got things upside down again.
From: Boudewijn Dijkstra on 1 Apr 2010 03:40 Op Thu, 01 Apr 2010 06:09:46 +0200 schreef JosephKK <quiettechblue(a)yahoo.com>: > On Wed, 31 Mar 2010 00:31:23 +0200, Hans-Bernhard Br�ker > <HBBroeker(a)t-online.de> wrote: >> Didi wrote: >>> On Mar 30, 1:44 am, Hans-Bernhard Br�ker <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". > > This erroneous statement alone shows that you are ill prepared to > participate > in this discussion. If you think UDP "sits" on top of IP you are very > mistaken. > It is a parallel (at the same level) link/transport protocol. If you think that the link layer, internet layer and transport layer are all the same layer, then yes. But alas for you, OSI and TCP/IP do not agree with you. > Moreover, you desired email reply shows arrogant disregard for USENET > norms. Well, at least he didn't top-post. -- Gemaakt met Opera's revolutionaire e-mailprogramma: http://www.opera.com/mail/ (remove the obvious prefix to reply by mail)
From: Cesar Rabak on 1 Apr 2010 11:39 Em 1/4/2010 02:09, JosephKK escreveu: > On Wed, 31 Mar 2010 00:31:23 +0200, Hans-Bernhard Br�ker<HBBroeker(a)t-online.de> wrote: > >> Didi wrote: >>> On Mar 30, 1:44 am, Hans-Bernhard Br�ker<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". > > This erroneous statement alone shows that you are ill prepared to participate > in this discussion. If you think UDP "sits" on top of IP you are very mistaken. > It is a parallel (at the same level) link/transport protocol. If you think you have a lesson to teach please: Can you show the erroneous part of the statement explaining us how an UDP datagram could be *sent* to a network without the IP layer? Remember *you* wrote they're 'parallel' so they can be used in exchange of each other, right? > > Moreover, you desired email reply shows arrogant disregard for USENET norms. Your not very informed reply shows an arrogrant ignorance for the Internet RFC or equivalent ISO models. -- Cesar Rabak GNU/Linux User 52247. Get counted: http://counter.li.org/
From: markp on 1 Apr 2010 11:49
"Cesar Rabak" <csrabak(a)bol.com.br> wrote in message news:hp2enu$7tr$1(a)news.eternal-september.org... > Em 1/4/2010 02:09, JosephKK escreveu: >> On Wed, 31 Mar 2010 00:31:23 +0200, Hans-Bernhard >> Br�ker<HBBroeker(a)t-online.de> wrote: >> >>> Didi wrote: >>>> On Mar 30, 1:44 am, Hans-Bernhard Br�ker<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". >> >> This erroneous statement alone shows that you are ill prepared to >> participate >> in this discussion. If you think UDP "sits" on top of IP you are very >> mistaken. >> It is a parallel (at the same level) link/transport protocol. > > If you think you have a lesson to teach please: > > Can you show the erroneous part of the statement explaining us how an UDP > datagram could be *sent* to a network without the IP layer? > > Remember *you* wrote they're 'parallel' so they can be used in exchange of > each other, right? > >> >> Moreover, you desired email reply shows arrogant disregard for USENET >> norms. > > Your not very informed reply shows an arrogrant ignorance for the Internet > RFC or equivalent ISO models. > > -- > Cesar Rabak > GNU/Linux User 52247. > Get counted: http://counter.li.org/ Add to that the datagram part can have a length of 64Kbytes, to send that over the internet will require splitting into max MTU packet sizes and then re-assembled. Of course UDP sits above IP!! Mark. |