/etc/network/interfaces strange behaviour

Mario Spinthiras mspinthiras at gmail.com
Fri Jun 20 18:37:27 UTC 2008


I recently setup a server which I had originally assigned a DHCP
address from the interfaces file using the line "iface eth0 inet dhcp"
. After I had put the machine on the rack I simply changed the
addressing to static and restarted the networking. This all went well
for a while. Today the machine had lost its power feed and as a result
the machine was offline for a while.
When the machine came back up (power) , it got an address by DHCP
though the settings in the interfaces file said static with all
relevant addressing. This is not something new to me , I have dealt
with Linux machines for almost 10 years now. I just cannot seem to
understand why it did this. Checking the interfaces file again , the
only thing I had seemed to forget is the broadcast
directive which denotes the network number and nothing more.

I have played with the way ifup parses this file and cannot seem to
derive a bug of somekind. Here is a thought though. I believe the
previously retrieved address from DHCP is cached somewhere (though Ive
searched high and low for it) and when "something" triggers the
parsing error , it goes back to that DHCP previously assigned address.
Can I have your thoughts on this? Its extremely strange behavior and I
cannot understand how a broadcast directive that was missing would
cause this problem. Note that the addressing that is static and the
DHCP assigned address are both in the same subnet. Is there a force
feature of somekind that tells it to go DHCP in a certain "case" ?

Possible ifupdown bug?

Warm Regards,
Mario A. Spinthiras
Blog: http://www.spinthiras.net
Mail: mspinthiras at gmail.com
Skype: smario125

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