Date: Wed, 12 Aug 1998 00:39:40 -0700 From: Peter Haight <psh1@cornell.edu> To: Doug White <dwhite@resnet.uoregon.edu> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Setting up two way PPP connection. Message-ID: <199808120739.AAA07324@wartch.sapros.com>
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>Your ISP will do that? That usually costs them mega-bucks. Well, this is all a centrex ISDN thing, so maybe it is cheaper than with modems. Anyway, I hacked the user-level ppp guy to handle this situation. It now listens for RINGs on the ISDN TA as well as watching for packets on the tun device. So that problem is solved. >> 2. The ISP has given me an 8 IP subnet. Their router routes all packets to >> one address which is the other end of the PPP line. In order to do this I >> had to use two IP addresses for my router. One was the IP address on the >> local lan and the other is the one it gets from the PPP line. Is there some >> way to avoid this? Can I set the PPP link up as some kind of bridge instead? > >No, ppp doesn't support bridging. You'll have to work it so both ends get >the same IP regardless. Then you can config pppd to give the remote the >IP it normally gets when you dial in. I'm not following you. I'll try and explain better. Normally my network is 10.0.0.0/29. I configure my router to have the IP 10.0.0.1. I gave the other machine on the network 10.0.0.2. Both of them have netmasks of 255.255.255.248. At this point I can ping everyone and everyone is happy. Now I dial into my ISP. I tell my ISP that I want to use 10.0.0.1 as my IP. It says OK and that the gateway is 10.0.2.21. Now ppp does the following: It creates the tun0 device with IP 10.0.0.1. It then makes 10.0.2.21 the default route. Now when I try to ping 10.0.0.2 it doesn't work. The reason (I think) is that the routing table says to route anything in the 10.0.0.0/29 subnet through 10.0.0.1. At this point both ed0 and tun0 have 10.0.0.1 as their inet address. I'm not exactly sure what FreeBSD decides to do in this situation, but it doesn't work. I can ping any host out on the Internet at this point, though. I thought I could fix this by adding ADD 0 0 INTERFACE to the ppp.linkup file, but whenever I try to send a packet to the Internet in this mode, I get an error like "Address family not supported". If I look at the routing table, the default route is to tun0 and there is no IP address specified. Do I just need to use two IP addresses for the router or is there something I'm missing? To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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