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Re: [TCLUG:10119] IP Routing question
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)
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"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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