iptables

[Tom H]

On Fri, Dec 7, 2012 at 5:53 PM, JD <jd1008 at gmail.com> wrote:
> On 12/07/2012 03:13 PM, Tom H wrote:
>> On Fri, Dec 7, 2012 at 4:25 PM, JD <jd1008 at gmail.com> wrote:
>>> On 12/07/2012 10:33 AM, Tom H wrote:
>>>> On Fri, Dec 7, 2012 at 11:43 AM, JD <jd1008 at gmail.com> wrote:


>>>>> I just ran nm-tool and it reports - Device: wlan0
>>>>> ---------------------------------------------------------------- Type:
>>>>> 802.11 WiFi Driver: ath9k State: unmanaged Default: no HW Address:
>>>>> 00:23:80:00:03:0A So how is it that NM no longer manages wlan0? And why is
>>>>> it set to default to no? It was coming up just fine before In installed ufw
>>>>> and enabled it. In fact, I was on wifi connection when a respondent to my
>>>>> question re: iptables, suggested I use ufw.
>>>>
>>>> Do you have any NIC other than "lo" defined in
>>>> "/etc/network/interfaces"?
>>>
>>> The is the default interfaces file that came with the installation of
>>> 12.10 or it was inherited from 12.04: auto lo eth0 wlan0 allow-hotplug eth0
>>> iface lo inet loopback
>>
>> 1) "allow-hotplug" isn't used in Ubuntu, which uses "allow-auto" (or its
>> shorter equivalent, "auto").
>
> Thanx Tom, But, I did not add the "allow-hotplug"
> So why is it there in the first place?

It's used in Debian and beings up NICs in conjunction with udev. It
cannot have landed there on its own.


>> 2) If you don't set "managed=true" in the "ifupdown" section of
>> "/etc/NetworkManager/dispatcher.d/01ifupdown", NM won't manage a NIC defined
>> in "/etc/network/interfaces".
>
> But the file /etc/NetworkManager/dispatcher.d/01ifupdown
> does  not even have
> managed=false
> and it comes from the full install.
> So, why would it require the user to add
> managed=true
>
> It seems to me that ubuntu truly is lacking in rubust NM and network
> interfaces management software.
> They user should NEVER have to edit these system files.
> Much too dangerous and very prone to error.
> It should all be done by gui software with drop-down menus/choices ...etc.
> I am new to ubuntu, and I was hooping that it's system admin software was
> not left up to the user to edit such files, but rather to configure their
> content via a gui configuration tool.

Not "/etc/NetworkManager/dispatcher.d/01ifupdown",
"/etc/NetworkManager/NetworkManager.conf".

Sorry my mind was on your previous thread about iptables; I'd been
wondering about whether NM could trigger an iptables script in
"/etc/network/if-pre-up.d" and google pointed to that 01ifupdown
script. Sorry.

You have a non-standard setup ("allow-hotplug"!), so NM's not working
properly... My parents use Ubuntu and NM without a hitch and have been
doing so for years. If you just install Ubuntu out of the box, NM
works just fine - or ifupdown if NM's not installed. AFAIK there's no
GUI to manage ifupdown post-install. NM has a GUI, nm-applet, but
AFAIK you can't choose which NIC to control via NM and which not to
control from within it; that's a tick box that's sorely needed...

NM has plugins. Some of them deal with integrating the pre-NM
networking tools of a distro with NM. The Debian/Ubuntu one's called
"ifupdown" and the RH one's called "ifcfg-rh". These plugins are
activated by listing them in "/etc/NetworkManager/NetworkManager.conf"
and they're listed/activated by default in their respective distros,
But NM's, unsurprisingly, more seamlessly integrated into RHEL/Fedora.

In RHEL/Fedora, if NM's installed and enabled, it'll control a NIC
defined in "/etc/sysconfig/network-scripts/ifcfg-<nic>" unless the
latter includes a "NM_CONTROLLED=no" line (the default is
"NM_CONTROLLED=yes").

In Debian/Ubuntu, if NM's installed and enabled, it'll control a NIC
defined in "/etc/network/interfaces" if "managed=true" is set in
"/etc/NetworkManager/NetworkManager.conf", but the default's
"managed=false". There were two silly decisions that were made: 1)
setting "managed=false" as the default and 2) hiding the on/off switch
in "/etc/NetworkManager/NetworkManager.conf" rather than having it in
"/etc/network/interfaces".