Re: Confusion Reigns On Routing

Charles Scott (cscott@freeway.net)
Sun, 15 Oct 1995 20:55:23 -0400 (EDT)

Jim:
You need to consider your configuration as a group of subnets. Make a
decision on how large the subnets need to be and how many subnets you'd
like. Then determine what the subnet mask would be and lay out the
addresses so that all interfaces which are directly connected are in the
same subnet and all addresses on the other side of a router are in a
diferent subnet.
The other option you have is to add specific routing entries for each
address at each host--not the best way to start out.

Chuck Scott, Pres.
Freeway, Inc.
cscott@freeway.net

On Sun, 15 Oct 1995, Jim Flowers wrote:

> OK. I admit it. I'm confused.
>
> I thought I understood routing enough to set up an IRX-114 and a PM2e as a
> dial-in hub. In order to test it before our leased-line is installed it
> seemed a piece of cake to just use S0 on the IRX-114 to connect via PPP to
> a dial-in port on one of our BSDI2.0 Digiboard ports.
>
> And so it was. bsdi.my.net and router1.my.net talk nicely and ping in both
> directions and telnet is handy to configure router1. I can also ping
> pm1.my.net from router1.my.net and vice versa and telnet from pc.my.net to
> either router1.my.net or pm1.my.net.
>
> In fact, the only problem is that I can't ping from bsdi.my.net through the
> S0 on router1 to either pm1.my.net or pc.my.net and I can't ping
> bsdi.my.net from either the pm1 or the pc. In short, my router isn't.
>
> I am assuming that I can "patch" the two segments of a network together
> with a router through a dial in port and the bidirectional pinging of bsdi
> and router1 seem to support that. So I must have something wrong in the
> configuration.
>
> +-----------------+
> | internet.my.net | 198.30.158.1
> +---------+-------+
> |
> |
> +-------+-----+
> | bsdi.my.net | 198.30.158.2
> +-------+-----+
> |
> +--------+-------+ ifconfig ppp? inet 198.30.158.2
> | digiboard port | 198.30.158.193 netmask 255.255.255.0
> +--------+-------+
> |
> |
> +---+---+ +---+---+
> | modem +---+ modem |
> +-------+ +---+---+
> |
> |
> |
> | port s0
> |
> +-------+--------+
> set gateway 198.30.158.2 +--+ router1.my.net | 198.30.158.193
> | +----------------+
> |
> | +----------------+
> set gateway 198.30.158.193 +--+ pm1.my.net | 198.30.158.200
> | +----------------+
> |
> | +----------------+
> set gateway 198.30.158.193 +--+ pc.my.net | 198.30.158.3
> +----------------+
>
> The netmasks are all the same (255.255.255.0) and routing is on for both
> pm1 and router1. Ifconfig output is reasonable but I don't understand the
> routing table.
>
> router1> show route
>
> 0.0.0.0 198.30.158.2 NS 1 ptp0
> 198.30.158.2 198.30.158.2 HL 1 ptp0
> 199.30.158.0 198.30.158.193 NL 1 ether0
>
> pm1> show route
>
> 0.0.0.0 198.30.158.193 NS 1 ether0
> 198.30.158.2 198.30.158.193 HD 2 ether0
> 199.30.158.0 198.30.158.200 NL 1 ether0
>
> Would appreciate a pointer to the problem area from anyone has read this
> far. Moss on the north side of the tree or halo around the moon or
> whatever as I have already done what I think is right.
>
> Thanks,
>
> Jim
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