[LFS Trac] #2057: Udev-122

Gerard Beekmans gerard at linuxfromscratch.org
Thu May 22 07:26:16 PDT 2008

>> Enhance the network boot scripts to first check for a link before assigning
>> the IP address.
> Would this work?  You would have to know the ip address of the gateway attached 
> to the network card.  If two cards have the same ip address, will the system try 
> to sent outbound packets via both cards?

When you configure a static IP address you know the IP of the gateway 
already - it's your "default gateway" setting. Presumably the gateway 
can only be pinged from one physical interface so if you get a ping, you 
matched the right IP to the right card. There are exceptions to this 
(multi-homed, firewall'ed gateways that don't ping, etc...)

> If the cards required different drivers, you could build the kernel with only 
> one driver and thus ensure only eth0.

Aren't we back to square one after you enable more drivers. Then after 
the first reboot of "kernel with additional drivers" you have to go 
through the discovery again of which card has which name assigned.

> The question is whether we want to tackle this in the book or not.  It does seem 
> to be a bucket of worms and so specialized that it really doesn't belong in the 
> book.

Because the scenarios are so varied this would take up an entire chapter 
in the book just to cover them all in a readable manner. Putting that 
information in an appendix would help to maintain the flow of the book 
without too many "if then else" scenarios. For those cases, put a note 
in chapter 7's network config to skip ahead to Appendix X and read up on 
what can be done and if a scenario matches the builder's.

Yes this could be a wiki or hint as well of of course. Seeing networking 
is already in the book, an appendix in the same book would be convenient.


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