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Re: [TCLUG:10119] IP Routing question



the default gw on bigdaddy and dan should be cerberus and the
dns on bigdaddy and dan chould be cerberus
cerberus should then receive all packets from bigdaddy and dan use its dns and
forward to the intended recipient
or
use cerberus' host table to determine ip <--> hostname translation, but bigdaddy
and dan still use cerberus as the primary DNS

is either of these the case?

Ben Kochie wrote:

> what is the default gateway set to on bigdaddy and dan?
> also.. what is
> cat /proc/sys/net/ipv4/ip_forward
>
> Thank You,
>         Ben Kochie (ben@nerp.net)
>
> *-----------------------*  [ - * - * - * - * - * - * - * - ]
> | Unix/Linux Consulting |  [ Haiku Error Message:          ]
> |  PC/Mac Repair        |  [  Chaos reigns within.         ]
> |   Networking          |  [  Reflect, repent, and reboot. ]
> | http://nerp.net       |  [  Order shall return.          ]
> *-----------------------*  [ - * - * - * - * - * - * - * - ]
>
>  "Unix is user friendly, Its just picky about its friends."
>
> On Mon, 15 Nov 1999, Ry4an Brase wrote:
>
> > I spent many hours last night pulling my hair out over this one and
> > hopefully someone can help:
> >
> > I've got a box (cerberus) with two NICs.  Each NIC has a cross-over cable
> > that connects it to antoher nic in a differnt box (bigdaddy and dan).  The
> > cerberus/bigdaddy link is 100Mb and has LinkSys PCI cards at each end of
> > the crossover.  The cerberus/dan link is 10Mb and has D Link22x (NE2000
> > clone) ISA cards at each end of the crossover.
> >
> > I've got the 100Mb net set up with IPs in the 192.168.100.x range, and the
> > 10Mb set up with IPs in the (you guessed it) 192.168.10.x range.  I've got
> > the two end nodes (bigdaddy & dan) set up with nothing in their routing
> > tables except an entry that points the default route towards cerberus.
> >
> > cerberus (the one w/ the two NICs) has a routing table like this:
> >
> > Kernel IP routing table
> > Destination     Gateway         Genmask         Flags Metric Ref  Iface
> > 192.168.100.1   *               255.255.255.255 UH    0      0    eth1
> > 192.168.10.1    *               255.255.255.255 UH    0      0    eth0
> > 192.168.100.0   *               255.255.255.0   U     0      0    eth1
> > 192.168.10.0    *               255.255.255.0   U     0      0    eth0
> > 127.0.0.0       *               255.0.0.0       U     0      0    lo
> >
> > So nearly as I can tell that should be all that's needed for things to
> > route to each other.
> >
> > Just for completeness here's the ipchains config on cerberus
> >
> > Chain input (policy ACCEPT):
> > Chain forward (policy ACCEPT):
> > Chain output (policy ACCEPT):
> >
> > Here are the ifconfig entries for the two NICs in cerberus:
> >
> > eth0      Link encap:Ethernet  HWaddr 00:80:C8:FA:72:9C
> >           inet addr:192.168.10.1  Bcast:192.168.10.255  Mask:255.255.255.0
> >           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> >           RX packets:9056 errors:0 dropped:0 overruns:0 frame:0
> >           TX packets:31 errors:0 dropped:0 overruns:0 carrier:0
> >           collisions:0 txqueuelen:100
> >           Interrupt:3 Base address:0x280
> >
> > eth1      Link encap:Ethernet  HWaddr 00:A0:CC:28:45:A2
> >           inet addr:192.168.100.1 Bcast:192.168.100.255 Mask:255.255.255.0
> >           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> >           RX packets:6426 errors:0 dropped:0 overruns:0 frame:0
> >           TX packets:73 errors:0 dropped:0 overruns:0 carrier:0
> >           collisions:0 txqueuelen:100
> >           Interrupt:11 Base address:0xe800
> >
> > There, with all that as background, let me tell you what is or isn't
> > working.
> >
> > WORKING:
> >       pinging cerberus to bigdaddy
> >       pinging cerberus to dan
> >       pinging dan to cerberus
> >       pinging bigdaddy to cerberus
> >       pinging bigdaddy to the 'far' NIC in cerberus
> >               (ex: 192.168.100.3 (bigdaddy) to 192.168.10.1)
> >         pinging dan to the 'far' NIC in cerberus
> >                 (ex: 192.168.10.2 (dan) to 192.168.100.1)
> >
> > NOTWORKING:
> >       pinging bigdaddy to dan
> >       pinging dan to bigdaddy
> >
> >
> > NOTES:
> >
> > I'm pretty sure the default routes on the end nodes (dan and bigdaddy) are
> > ok, and the boxen do route all requests through their NICs (flicker in the
> > activity lights).
> >
> > GUESSES:
> >
> > Perhaps I need something to tell cerberus it's ok to connect the two?
> > Soemthing in the forward rule? A 1 written to a file in /proc? A blood
> > sacrifice?
> >
> > Cerberus is running whatever kernel comes with rh 6.1.  Ifn' I get this
> > working I'll build up a kernel that's optimized for routing, but I didn't
> > think it was necessary to get it to work at all.
> >
> > ADVICE I'VE RECEIVED:
> >
> > "Only high end NICs will hand off packets for routing.  Put Intel, 3COM,
> > or (real) NE2000 NICs in cerberus."  If that's true why the hell wouldn't
> > O'Reilly's _TCP Network Administration_ mention that little catch? If I
> > can't hear any better suggestions I'll get new NICs, but if (and I may be
> > wrong) routing is done at the OS level what does it matter to the NIC if
> > the packet will be given to antoher NIC or used at the host?
> >
> > Thanks in advance for any clock cycles you can waste on this,
> > Ry4an
> >
> > --
> > Ry4an Brase - http://ry4an.org - 612-623-9946
> > 'If you're not a rebel when you're 20 you've got no heart; if
> >  you're  not establishment when you're 30 you've got no brain.'
> >
> >
> >
> >
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