[TriLUG] reliably get network devices

[Josh Vickery]

When I'm faced with a system that likes to change the order in which
NICs are detected (and thus named) I turn to ifrename, but udev can
also take care of this issue as well. This looks like it's a pretty
good article on the subject:
http://www.debian-administration.org/articles/502

Josh

On Tue, Jun 24, 2008 at 8:24 AM, Reginald Reed <reginald.reed at gmail.com> wrote:
> I'm curious as to why you wouldn't want to use MAC addresses.  I
> combination of the MAC + ifconfig output would be pretty good mapping
> of physical to logical.  Since, in most instances, the MAC address of
> a NIC wouldn't change, you could easily determine the mapping to ethX
> on any boot.
>
> What am I missing?
>
> --Reggie
>
> On Tue, Jun 24, 2008 at 7:00 AM, Kevin Hunter <hunteke at earlham.edu> wrote:
>> At 6:28a -0400 on Tue, 24 Jun 2008, Carl Crider wrote:
>>> Don't know if this is what you are looking for. Maybe I'm just confused by
>>> the question.
>>
>> Heh, then perhaps I'm not asking the question I think I'm asking!
>>
>>> ifconfig -a
>>>
>>> ifconfig | less
>>
>> This is the next step in what I want to do.  The problem is that this
>> will return what the OS has, but what the OS has (or provides) does not
>> appear to be a guaranteed or set mapping.  That is eth0 might be one NIC
>> card on one boot, then the other on a different boot.  I'm looking for a
>> consistent mapping.  I could use the MAC addresses, but then I'm back to
>> individually identifying cards, which is not an option.
>>
>> I wonder if the underlying problem is that the OS uses the
>> non-deterministic "order in which they respond to a probe" to be the
>> order of the NICs, in which case I may be up a creek.  I hope not.
>>
>> So, how do I dynamically (programmatically) probe what NICs are
>> available and get a consistent mapping?
>>
>> Thanks,
>>
>> Kevin
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