Re: networkmanager-0.9.8.8 will not connect to ipv4 wired network

[Dan Williams <dcbw redhat com>]

On Sat, 2014-04-05 at 12:54 +0000, John Frankish wrote:
> Using networkmanager-0.9.8.8 and dhcpcd-6.3.2, I am unable to connect to a wired connection eth0.
>
> If networkmanager is stopped, dhcpcd will connect without problems.
>
> The problem appears to be that networkmanager is stuck in a loop trying to make an ipv6 connection when the 
> connection is ipv4 - ipv6 is disabled on the router.

The reason is that there is another dhcpcd process running, while
NetworkManager needs a private dhcpcd process, because it needs to
receive the options back from the dhcpcd that it runs.  More info
below...

> There is another minor issue in that networkworkmanager is looking for hosts in /usr/local/etc rather than 
> /etc, but adding a symlink does not resolve the issue.

/usr/local/etc would be due to a configure-time issue, like many
projects when you're running configure, you need to specify
"--prefix=/usr --sysconfdir=/etc --localstatedir=/var" to put things in
the right place, otherwise it will default to /usr/local to avoid
overwriting your existing installation.

> Is there some way to disable ipv6 in a networkmanager conf file?

IPv6 is disabled in each connection profile by setting the IPv6
configuration "method" to "ignore".  So for a keyfile, you would use:

[ipv6]
method=ignore

or just pick that method in the various GUI editors.

> dhcpcd[30849]: dhcpcd already running on pid 30823 (/var/run/dhcpcd-eth0.pid)
> NetworkManager[30842]: <info> (eth0): DHCPv4 client pid 30849 exited with status 1

Here, the private dhcpcd that NetworkManager spawns with the options
that NetworkManager requires, has noticed that there is another dhcpcd
process running.  You can't have two DHCP clients running for the same
interface, otherwise they'll fight over which one handles DHCP.  So you
don't want the one you ran manually above to continue running when
you're using NetworkManager.

Dan