Date: Thu, 15 Jun 2000 14:20:15 -0600 (MDT) From: Nick Rogness <nick@rapidnet.com> To: nino@inode.at Cc: "Marinos J . Yannikos" <mjy@pobox.com>, hackers@freebsd.org Subject: Re: routing bug(?) persists (PR 16318) Message-ID: <Pine.BSF.4.21.0006151338370.69565-100000@rapidnet.com> In-Reply-To: <20000615211926.K24505@TK147108.telekabel.at>
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On Thu, 15 Jun 2000, Marinos J . Yannikos wrote:
> On Thu, Jun 15, 2000 at 11:44:14AM -0600, Nick Rogness wrote:
> > > route_0="-net 195.58.161.96 -netmask 255.255.255.240 -iface vr0"
> > What IP is that network reachable through?
>
> vr0 has only one IP - 195.58.183.77
That's not likely unless you are dialed up (with your net
interface that's not likely) or running some type of bridge, like
a cable modem or a DSL bridge.
Your IP is actually part of some subnetwork, more than likely.
Otherwise how does your upstream provider route packets to you
through their network...static routes??? maybe, if their idiots.
That would mean that every machine on that net would have to have
a static route to your machine right? What is the network
topology like?
BUT if you think that is how you are setup you can use ipfw to
accomplish your task:
ipfw add 450 allow ip from any to any in via vr0
ipfw add 500 fwd 195.58.161.97 ip from any to any
Then:
route add -net 195.58.161.96 -netmask 255.255.255.240 -interface vr0
Doesn't that basically setup a default route? How they get to
your machine is their problem.
>
> > WHat does your routing table look like before this route gets
> > added? after it gets added?
>
> Before, it (probably) only contains the localhost route, afterwards it
> looks like this:
>
> Destination Gateway Flags Refs Use Netif Expire
> default 195.58.161.97 UGSc 0 192 vr0
> 127.0.0.1 127.0.0.1 UH 0 209212 lo0
> 195.58.161.96/28 link#1 UCSc 0 0 vr0
> 195.58.183.72/29 link#1 UC 0 0 vr0
> 195.58.183.77 0:50:ba:c5:6e:77 UHLW 0 80 lo0
>
> WRT your other e-mail,
> > The whole question is, What are you trying to accomplish?
>
> For some reason, there are 2 (actually more) distinct subnets within one
Probably VLAN's or they are trying to save IP space.
> physical network. Only one system has an outwards connection, but its internal
> IP lies in the other subnet and has no IP alias in "my" subnet. The idea is to
> set up a static route between the 2 subnets and then use the IP in the other
> subnet as the default gateway.
There should be an IP on your subnet that you can reference
their network with...unless they have a messy static routing
table. Ask them how they are routing your IP to you?
> This is how a Linux box is set up in another connected subnet using the same
> default gateway (not that I consider Linux to be a reference for a correct
> implementation, but it seems that most/all boxes in that server room are
> connected in a similar way):
>
> Kernel IP routing table
> Destination Gateway Genmask Flags Metric Ref Use Iface
> 195.58.161.48 0.0.0.0 255.255.255.240 U 0 0 0 eth0
> 195.58.161.96 0.0.0.0 255.255.255.240 U 0 0 0 eth0
> 127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
> 0.0.0.0 195.58.161.97 0.0.0.0 UG 0 0 0 eth0
>
hmmm. OK. THis just makes no sense to do it this way. Static
routes are the only thing besides some bizarre VLAN setup that
could work.
I would look at your arp table, possible run tcpdump to see if
these guys are setup the way they say they are. If they are on
the same physical network, then you should be able to ping
there machine without any default gateway and just that 1 static
route out the interface.
I would like to know how, and why, they are doing this. If it is
to conserve IP space, NAT is a far better solution.
Nick Rogness
- Speak softly and carry a Gigabit switch.
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