howto isolate 2 nics?

Mikkel L. Ellertson mikkel at infinity-ltd.com
Fri Sep 22 18:57:53 UTC 2006


Gene Heskett wrote:
> On Friday 22 September 2006 14:00, Mikkel L. Ellertson wrote:
>> Gene Heskett wrote:
>>> I got this back, but I'll sanitze the outside addresses to protect the
>>> guilty. :-)
>>>
>> The default route is through eth1 with a gateway of 192.168.1.12. It
>> should be through eth0 with what ever gateway address is provided by
>> the ISP.
> 
> And then the local machines servers are not usable at the local address 
> using the local version of its FQDN, so this isn't a working option.
> 
That sounds like another issue entirely. Are they accessible using
the IP address? If so, then what does /etc/resolv.conf look like? It
could be that by changing the default route, the system no longer
knows how to access the local name server.

>> This is why traffic for the Internet, that should go out 
>> eth0, is going out eth1. It looks like the default route was set the
>> way it was in order to get to the 169.254.0.0 network through
>> 192.168.1.12 instead of providing a proper route to that network. If
>> this is the case, then what is needed instead is a route specificity
>> for 169.254.0.0 using 192.168.1.12 as the gateway.
>>
> The 169 address is a red herring, that like 3 day old fish, should be 
> thrown out.  Its a redhat/fedora artifact I believe, for what useage I 
> have no idea.  All I know is its there on every fedora machine since about 
> FC3 or 4, my lappy FC5 has it, and it is not setup in any config file 
> anyplace.  And it is not part of any network or subnet at that site.
> 
> I think we're losing track of the real problem by being distracted by the 
> 169 address.  We'd kill it if we knew how to do it.
> 
> Thanks, Mikkel

Does the machine at 192.168.1.12 have more then one NIC? Is it by
any chance running the name server for your local network, or
providing access to it? We may need to know more about your local
network setup to properly fix things

>From the sounds of things, the default route was put in to fix a DNS
problem, instead of fixing it properly. So we have to fix that, as
well as get your routing working properly. DNS for the local network
should not depend on the default route using 192.168.1.12 as your
default gateway. Unless that machine has more then one NIC, and the
second NIC provides a connection to another network, it should not
be a gateway at all. If it does provide access to another network,
then you need to define routes to those networks.

Mikkel
-- 

  Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!




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