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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.ecn.uoknor.edu!qns3.qns.net!imci4!newsfeed.internetmci.com!news.mathworks.com!fu-berlin.de!main.Germany.EU.net!Dortmund.Germany.EU.net!interface-business.de!usenet From: j@ida.interface-business.de (J Wunsch) Newsgroups: comp.unix.bsd.bsdi.misc Subject: Re: Multiple Network IP's on one NIC? Date: 7 Aug 1996 16:18:16 GMT Organization: interface business GmbH, Dresden Lines: 20 Message-ID: <4uafk8$kpk@innocence.interface-business.de> References: <4tk3ef$hb7@access5.digex.net> <4u4i0r$b8@anorak.coverform.lan> Reply-To: joerg_wunsch@interface-business.de (Joerg Wunsch) NNTP-Posting-Host: ida.interface-business.de X-Newsreader: knews 0.9.6 X-Phone: +49-351-31809-14 X-Fax: +49-351-3361187 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E brian@awfulhak.demon.co.uk (Brian Somers) wrote: > Hang on, if you want the same NIC to talk to both subnets, routing is > useless - you can't route something back onto a wire that it came off - > it's already been there..... Well, i think you can actually do it. It's a little pointless at the first glance, but if you perhaps have only one machine in the net that can talk to two different subnets on the same interface (ifconfig alias), it could make sense. It's full-featured routing then, i.e. the packets are being resent by the router with its Ether address, and the TTL is counted down by one. (The original sender could not ARP resolve the destination address since it thought it's in a different physical network. The `gateway' however knows about both logical nets, and therefore can ARP for the destination.) -- J"org Wunsch Unix support engineer joerg_wunsch@interface-business.de http://www.interface-business.de/~j