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- Path: lebunka.ion.com.au!news
- From: Mark Constable <markc@ion.com.au>
- Newsgroups: comp.os.linux.networking,comp.unix.admin,comp.unix.misc,comp.unix.questions,comp.unix.amiga
- Subject: Re: SLIP gateway on a local network
- Date: Thu, 28 Mar 1996 13:55:58 +1000
- Organization: ION Pty Ltd, Australia
- Message-ID: <315A0DCE.25B90DA2@ion.com.au>
- References: <314B4C05.7FD76F10@bbs.infosquare.it> <DoEHtq.51v@gaspode.mayn.de> <4ik1ho$suv@bell.maths.tcd.ie> <4ikcb0$r9g.C.deGroot@news.inter.NL.net> <4j250s$bab@jake.esu.edu> <4j8maf$108c@news-s01.ny.us.ibm.net>
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-
- Frederick V. Heitkamp wrote:
-
- > OK. What if you wrote to the NIC (or whatever it's called) and got your
- > own class C addresses for the two machines? Would you still need to do
- > the masquerading deal? Do you still need to tell your ISP?
-
- A whole C-class block for 2 machines ? Bit of a waste unless you are going
- to use them for other things. Your ISP allocates you 1 IP (maybe dynamically)
- otherwise you wouldn't be connected. You could use this 1 IP num and masquerading
- to allow other hosts on your end access to the net, or, if your ISP (big if) is
- co-operative you could ask for one more IP and see if they will add both IP
- nums to their routing tables - this is not much good unless you have a permanent
- connection though. If you have an ethernet on your end then another way is to
- get a subnet allocated to you by your ISP and you can manage it as you see fit.
-
- inet <-?-> isphost <-ppp-> yourhost-a <-ppp-> yourhost-b
-
- Simplest case of two static IP nums allocated to you by your ISP. When you dial
- in to isphost from yourhost-a you already have a default-route established by
- doing something like:
-
- /usr/sbin/pppd /dev/cua1 38400 crtscts modem defaultroute proxyarp 123.45.67.89:
-
- so when you ping anything other than yourhost-a or yourhost-b the packets will
- flow out to isphost, fine. Now, to get yourhost-b working you need to have
- isphost know about it, something like this needs to be done on isphost:
-
- route yourhost-b gw yourhost-a dev ppp0
-
- then on yourhost-b you need to do the reciprical:
-
- route isphost gw yourhost-a dev ppp0
-
- Without co-operation or root perms on isphost this is almost impossible to do
- but gives you a little idea of one approach. The whole issue is extremely complex
- and it would be excellent to have access to a small-time ISP C-class type FAQ
- on IP routing, as most examples I've seen relate to B-class blocks.
-
- --
- Mark Constable (+61 7 55275724)
- mailto:markc@ion.com.au
- http://www.ion.com.au/linus/markc
-