[PLUG] Red Hat routing follies

Ed Sawicki ed at alcpress.com
Mon Oct 27 06:49:02 UTC 2003


On Sun, 2003-10-26 at 19:21, Carla Schroder wrote:
> The weird part is I can't figure out how Red Hat determines which one to use. 
> They are configured the same:
<snip>
> 
>  The first time I booted it up, I had eth1 connected. But I couldn't get a 
> network connection until I moved the cable to eth0. Now RH has decided it 
> will use eth1.  How?

I avoid ambiguity by using multi-port Ethernet cards. I just built
a router/firewall that needed 5 interfaces. I used two 2-port
Intel cards and the motherboard-mounted interface. All use the
same Intel chip and the same driver. It always boots predictably.

When using different cards that require different drivers, I
compile the drivers into the kernel for better predictability.

So, overall has plug-and-play been a blessing or a curse?


> This looks weird too:
> 
> % /sbin/route
> 
> Destination	Gateway	Genmask		Flags	Metric	Ref	Use	Iface
> 192.168.1.0		*	255.255.255.0	U		0		0	0	eth1
> 192.168.1.0		*	255.255.255.0	U		0		0	0	eth1
> 169.254.0.0		*	255.255.0.0	U		0		0	0	eth1
> 127.0.0.0			*	255.0.0.0		U		0		0	0	lo
> default				192.168.1.1	UG		0		0	0	eth1
> 
> Wut the heck is going on here? How did eth1 get all the goodies? 

You should start using the iproute2 stuff instead of the classic
ifconfig and route commands - especially when you're assigning
interfaces addresses from the same block.


> where did 169.254.0.0 come from?

That's already been answered. Be aware that link local operation
is still being discussed by the IETF working group. Red Hat's
current implementation may not be the way we do it in the future.

Ed





More information about the PLUG mailing list