[Dnsmasq-discuss] Removing a feature does anyone rely on this?

[Ed W]

On 02/07/2012 08:30, Helmut Hullen wrote:
> Hallo, Vincent,
>
> Du meintest am 02.07.12:
>
>>> But it seems to be a bit more difficult to change
>>> automatically something like
>>>
>>>      dhcp-range=eth0,192.168.0.10,static
>>>      dhcp-range=eth1,192.168.1,10,static
>>>      dhcp-range=eth2,192.168.17.10-192.168,28.250
>>>
>>> to
>>>
>>>      dhcp-range=eth0,192.168.0.10,static
>>>      dhcp-range=eth2,192.168.1,10,static
>>>      dhcp-range=eth1,192.168.17.10-192.168,28.250
>>>
>>> when the names of eth1 and eth2 have changed.
>> What about [re]naming those interface names using udev, i.e.
>> xx-persistent-net.rules file in /etc/udev/rules.d/ ?
> That moves the problem from one place to another. I don't like "udev", I
> don't use "udev". Especially with more than 1 NIC it makes more problems
> than it solves.
>

Although you don't like udev, I think it's an important part of your 
final solution.  Quite possibly it's already working (as intended) and 
is the reason you observe some of the effects that you do? Without a 
udev solution anything you come up with is likely more brittle than 
needs to be.  I don't mean to imply that you shouldn't do what you are 
doing (although I'm unsure what your config would be to do what you want 
to do), but do learn about udev as well

On your machine check /etc/udev/rules.d/70-persistent-net.rules (could 
be something slightly different on different distros though)

Many distros will automatically maintain a file with lines like:
# PCI device 0x10ec:0x8168 (r8169)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", 
ATTR{address}=="00:1d:7d:05:f2:30", ATTR{type}=="1", KERNEL=="eth*", 
NAME="eth2"

There is even a script to add these lines and you can quite easily hack 
it and plug in your own script (use copy and paste?) which generates 
lines like the above based on the system detected at boot (say)

Also I need to do some highly dynamic config and what I do is use the 
script feature of dhcpcd (which works for static and dynamic config, 
it's more than just a dhcp client).  This builds various configs for me 
on demand.  Couple that with the ability for dnsmasq to accept config 
files in pieces, plus it's dbus access, and you can actually achieve 
very dynamic configs without too much trouble. Perhaps examine the 
scripts in the openresolv package for inspiration (this builds dns 
configs dynamically for dnsmasq)

Good luck

Ed W