Subject: Re: Routing issue (no route to default host)
To: Anthony Lieuallen <arantius@yahoo.com>
From: Seth Kurtzberg <seth@cql.com>
List: tech-net
Date: 02/14/2003 10:35:26
I was the one who posted the incorrect info.  Apologies.

The cable modem is almost always the DHCP server for a cable modem 
installation.  That said, I don't see why it matters here.

Also, the cable modem has to be the destination for the default route.  What 
you can then do is make the default destination _for the cable modem_ the 
default gateway.  You can do this with most cable modems.

On Friday 14 February 2003 10:11 am, Anthony Lieuallen wrote:
> --- Alan Barrett <apb@cequrux.com> wrote:
> > You seem to think that NetBSD has a hard-coded refusal to route to
> > 10.x.x.x addresses.  I am sure that there's no such thing.
>
> As to this, someone had previously posted they suspected this was the
> reason.  They were wrong =)
>
> > Now, addressing your original question:
> > > >  > Situation is the cable modem service here.  All that is
> >
> > available
> >
> > > >  > is a "one-way" cable modem (asynchronus, cable downlink,
> >
> > analog
> >
> > > >  > phone modem uplink), and the strange way the cable modem's
> > > >  > hardware seems to operate.  It assigns me a public address of
> > > >  > 209.122.183.50, while the default router is at 10.17.44.244 .
> >
> > They should be allocating you an address in the same subnet as your
> > default gateway.  Either they are crazy or you didn't understand what
> > they intended.
>
> Yes, it seems to me to be a crazy setup as well.  The DHCP server as
> well as router seem to be within the modem, not at their end.  This is
> the only reason I can find for it using a private address.
>
> > > >  > In short, I am never able to add a route to that address, as
> > > >  > there is no route to the 10.x.x.x subnet.
> >
> > Right.  If your provider is crazy and really intends this setup to
> > work, then you will need to add a route to the 10.x.x.x subnet.  Try
> > something like this:
> >
> >     route add -net 10.0.0.0 -netmask 255.0.0.0 -interface
> > 209.122.183.50
> >
> > This should works adequately if the interface has a unique IP
> > address.  I have never understood why the NetBSD "route add" command
> > doesn't take an interface name in this context.
>
> I assure you I've tried this =)  I agree, it would probably work better
> if I could just give an interface name.  (As in my original post, this
> is how I have worked around the solution, I have managed to make linux
> route packets for that IP to the appropriate interface.)  Unfortunately
> that does not seem to work.  Below is a session that contains the best
> I've managed to achieve.  Basically, I got it to route packets for the
> 10.x.x.x subnet to the correct place, and I managed to ping that IP
> (though I did not try to verify if that was really going out to the
> modem, or maybe trapped in a loopback or something).  I added an arp
> entry just in case (It has been suggested before, and usually not
> worked).  But then, I am still unable to add a default route to that
> IP.
>
> (Sorry I know.. this is a little big....)
>
> paranoid:~:root:{505} netstat -f inet -nr
> Routing tables
>
> Internet:
> Destination        Gateway            Flags     Refs     Use    Mtu
> Interface
> 127                127.0.0.1          UGRS        0        0  33228
> lo0
> 127.0.0.1          127.0.0.1          UH          2        2  33228
> lo0
> 192.168.1          link#2             UC          3        0   1500
> ep1
> 192.168.1.110      00:10:5a:0c:65:ed  UHLc        2      162   1500
> ep1
> 192.168.1.112      00:60:08:0a:4b:f9  UHLc        1        8   1500
> ep1
> 192.168.1.255      link#2             UHLc        2       37   1500
> ep1
> 209.122.183        link#1             UC          1        0   1500
> ep0
> 209.122.183.50     127.0.0.1          UGHS        0        0  33228
> lo0
> 209.122.183.255    link#1             UHLc        2       37   1500
> ep0
> paranoid:~:root:{506} route add -net 10 -interface 209.122.183.50
> add net 10: gateway 209.122.183.50
> paranoid:~:root:{507} netstat -f inet -nr
> Routing tables
>
> Internet:
> Destination        Gateway            Flags     Refs     Use    Mtu
> Interface
> 10                 link#1             UCS         0        0   1500
> ep0
> 127                127.0.0.1          UGRS        0        0  33228
> lo0
> 127.0.0.1          127.0.0.1          UH          2        2  33228
> lo0
> 192.168.1          link#2             UC          3        0   1500
> ep1
> 192.168.1.110      00:10:5a:0c:65:ed  UHLc        2      216   1500
> ep1
> 192.168.1.112      00:60:08:0a:4b:f9  UHLc        1        8   1500
> ep1
> 192.168.1.255      link#2             UHLc        2       37   1500
> ep1
> 209.122.183        link#1             UC          1        0   1500
> ep0
> 209.122.183.50     127.0.0.1          UGHS        0        0  33228
> lo0
> 209.122.183.255    link#1             UHLc        2       37   1500
> ep0
> paranoid:~:root:{508} ping 10.17.44.244
> PING 10.17.44.244 (10.17.44.244): 56 data bytes
> 64 bytes from 10.17.44.244: icmp_seq=0 ttl=254 time=3.610 ms
> 64 bytes from 10.17.44.244: icmp_seq=1 ttl=254 time=3.763 ms
> 64 bytes from 10.17.44.244: icmp_seq=2 ttl=254 time=3.766 ms
> ^C
> ----10.17.44.244 PING Statistics----
> 3 packets transmitted, 3 packets received, 0.0% packet loss
> round-trip min/avg/max/stddev = 3.610/3.713/3.766/0.089 ms
> paranoid:~:root:{509} route add default 10.17.44.244
> writing to routing socket: Network is unreachable
> add net default: gateway 10.17.44.244: Network is unreachable
> paranoid:~:root:{510} ping 10.17.44.244
> PING 10.17.44.244 (10.17.44.244): 56 data bytes
> 64 bytes from 10.17.44.244: icmp_seq=0 ttl=254 time=3.487 ms
> 64 bytes from 10.17.44.244: icmp_seq=1 ttl=254 time=3.733 ms
> ^C
> ----10.17.44.244 PING Statistics----
> 2 packets transmitted, 2 packets received, 0.0% packet loss
> round-trip min/avg/max/stddev = 3.487/3.610/3.733/0.174 ms
> paranoid:~:root:{511} arp -s 10.17.44.244 00:20:cd:02:f1:5a
> paranoid:~:root:{512} route add default 10.17.44.244
> writing to routing socket: Network is unreachable
> add net default: gateway 10.17.44.244: Network is unreachable
> paranoid:~:root:{513}
>
>
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-- 
Seth Kurtzberg
M. I. S. Corp.
480-661-1849
seth@cql.com