Harry Putnam wrote:
> Matthew Boeckman <[EMAIL PROTECTED]> writes:
>
>
>>I could be terribly wrong here, but my thinking is that the GW
>>statement in eth1 on m6 is being ignored (maybe check dmesg). I have
>>never assigned a static route in linux that did not show up in netstat
>
>
> It turns out your suggested experiment showed absolutely no difference
> with 192.168.1.1 knocked down as gateway from 192.168.1.5. Pinging ssh'
> ing etc, no problem. In fact route didn't know anything about it being
> up so it wasn't, just as you said.
>
> a simpler diagram:
>
> Not bothering with addresses for 1-4, illustrates what I tried out.
> Apparently I've been seized with temporary insanity (I hope its
> temporary anyway), because I don't see the odd behavior I reported now
> with a more structured experiment.
it took me awhile to learn the lesson, but in diagnosing network
problems I have found that the best, and only way to figure anything out
is to be very meticulous and structured. Change _one_ thing, then test.
Make no assumptions at all. I've been a netadmin (cisco/lucent/linux)
for 5 years now and every time i've had one of those ghost like problems
it has always been because i ASSumed something that proved to be wrong.
Networks are picky little b*tches, and you must respect them as such.
I still kind of wonder why that route statment in your ifcfg file was
being ignored... did you notice anything unusual in the dmesg output?
you could dmesg|grep route or the like to see.
List: Sorry for the OT discussion. Hopefully it may serve to assist
others from archive land that have similair network hiccups.
>
> XX=192.168
>
> INTERNET
> |
> DSL MODEM <STATIC IP>
> |
> NETGEAR router/firewall XX.0.1
> | |
> eth0 | XX.0.7 eth0 | XX.0.5
> mach6 mach5
> eth1 | XX.1.5 eth1 | XX.1.1
> ------ XX.1.1/24hub ---------------
> | | | |
> mach1 mach2 mach3 mach4
>
> Mach5 has gateway set to XX.0.1 (the netgear router)
>
> If, on mach 6 I knock down any gateway, netstat -nr shows:
> Kernel IP routing table
> Destination Gateway Genmask Flags MSS Window irtt Iface
> 192.168.1.0 0.0.0.0 255.255.255.0 U 40 0 0 eth1
> 192.168.0.0 0.0.0.0 255.255.255.0 U 40 0 0 eth0
> 127.0.0.0 0.0.0.0 255.0.0.0 U 40 0 0 lo
>
> In that config I can ping ssh etc to all 1-6 machines and the router
> XX.0.1 from mach 6 but can't get to the internet of course.
>
> ====================================================================
>
> Now setting XX.0.1(router) as default gateway, netstat now shows
>
> Kernel IP routing table
> Destination Gateway Genmask Flags MSS Window irtt Iface
> 192.168.1.0 0.0.0.0 255.255.255.0 U 40 0 0 eth1
> 192.168.0.0 0.0.0.0 255.255.255.0 U 40 0 0 eth0
> 127.0.0.0 0.0.0.0 255.0.0.0 U 40 0 0 lo
> 0.0.0.0 192.168.0.1 0.0.0.0 UG 40 0 0 eth0
>
> In this config I can ping ssh etc to all machine,router and internet
>>From mach 6
>
> ===================================================================
> Knocking down XX.0.1 as gateway and putting up XX.1.1
>
> netstat -nr now shows:
> Kernel IP routing table
> Destination Gateway Genmask Flags MSS Window irtt Iface
> 192.168.1.0 0.0.0.0 255.255.255.0 U 40 0 0 eth1
> 192.168.0.0 0.0.0.0 255.255.255.0 U 40 0 0 eth0
> 127.0.0.0 0.0.0.0 255.0.0.0 U 40 0 0 lo
> 0.0.0.0 192.168.1.1 0.0.0.0 UG 40 0 0 eth1
>
>
> I can still ping, ssh and get the internet.
>
>
>
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>
>
--
Matthew Boeckman (816) 777-2160
Manager - Systems Integration Saepio Technologies
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