Re: Weird ip stuff with NIC

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Thanks for the response. I've added some clarifying statements if you can 
shed any further light on the situation. 

On Fri, 11 Jan 2002, Glynn Clements wrote:

> 
> John Peel wrote:
> 
> > Then to test the setup I try to switch machine A over to an internal ip 
> > address (192.168.1.10). This has been done manually by editing 
> > /etc/sysconfig/network-scripts/ifcfg-eth0, as well as using linuxconf and 
> > netconfig. After doing this ifconfig shows that it still has the same 
> > address it last had when using dhcp.
> 
> 
> Note that editing configuration files (e.g. ifcfg-eth0) won't, in
> itself, change the NIC's settings. You would need to use something
> like:
> 
> 	/etc/rc.d/init.d/network restart
> 
	This is how I usually restart the network I just didn't include it 
in the e-mail, I also have tried ifup eth0 and had the same results

> > However a ping shows that it is using 
> > the internal ip.
> 
> In what way?
> 

PING 192.168.1.1 (192.168.1.1) from 192.168.1.10: 56(84) bytes of data.

> > and route shows that eth0 has two addresses the internal 
> > ip as well as the dhcp ip. 
> 
> "route" doesn't tell you anything about which IP addresses are bound
> to a NIC. It may tell you that a certain IP address is routed via a
> particular NIC, but that doesn't mean that the IP address is bound to
> the NIC.

I was unaware of how route actually worked but I guess the real issue is 
is that route was showing me an uotput similar to this:

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.168.1.10	192.168.1.1	255.255.255.0			      0	eth0
24.217.32.0     *               255.255.240.0   U     0      0        0 eth0
127.0.0.0       *               255.0.0.0       U     0      0        0 lo
default         ol1-24.217.32.1 0.0.0.0         UG    0      0        0 eth0

so while it wasn't telling me actuall information about the nic itself 
it was showing me one too many ips. I may still be way off on what this is 
actually showing but i was desperate and searching for an answer. 

> 
> > I have been able to get it to have only the internal ip by restarting the 
> > entire machine which should not be necessary. 
> 
> A reboot will (amongst other things) run:
> 
> 	/etc/rc.d/init.d/network start
> 
Yes but it would appear that it is also flushing out some other 
information regarding the nic because without a reboot running 
/etc/init.d/network restart results in the problems above but a reboot 
does not.

> > the next part isn't so important but once I get machine A to work properly 
> > I can ping itself, I can also ping the router but not the outside world. 
> > The router can ping itself and the outside world but not machine A. 
> 
> Does the router have the correct routing information for machine A?

Not really sure I am still getting started with routing. 
> 
> Are you using any form of NAT (e.g. masquerading) on the router? If
> not, then machine A definitely won't be able to talk to the rest of
> the Internet (it may be able to send packets, but those packets will
> have a source address of 192.168.1.10, so you won't get any replies).
>
as of right now my first goal is to set the router up as a masquerading 
server. back in 2.2 days I had no problems setting up masquerading which 
is why this is so frustrating. I have all of the proper modules loaded 
according to lsmod  but I really am not sure about having proper routing 
setup on the router for machine A. As a sidebar to this I know that 
machine B was getting hit from Machine A by looking at /var/log/messages I 
see  martian errors or something like that and machine As ip address is 
listed in the error. (Sorry i can't be more specific but I can't get the 
actual error from work.)

I don't know if this may help to diagnose my problem any more, or if the 
conclusion is just that my box is just plain screwy. Again any help is 
appreciated. Thanks, -peel

john peel
jrp@thepeel.org

> 


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