Re: Loss of Network Adress is DHCP Server failed for some hours

[Francesco Giudici <fgiudici redhat com>]

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On 02/10/2017 15:05, Oliver Freyermuth via networkmanager-list wrote:
> [...] Another option would be to increase the DHCP timeout, which
> seems to translate into the time "NetworkManager keeps dhclient
> alive before killing it".

That's right, this is the way we think should be addressed.

> Sadly, this can only be set per connection, which makes it hard to
> roll this out onto a large set of servers which should use default
> DHCP configuration.
Well, you can set it system wide. See:
https://bugzilla.redhat.com/show_bug.cgi?id=1350830#c7

> It would be really nice if NetworkManager would behave like *any*
> other DHCP client here, or just let dhclient do its job properly
> instead of killing it regularly, breaking the rule of least
> surprise.
>
> Any thoughts on this? Any help on the matter?

In NetworkManager you have the ipv4.may-fail=yes property.
So, NetworkManager takes into account that ipv4 (and so dhcp) may
fail, and would stop keeping trying the connection, but could mark the
connection as active if ipv6 succeeds.
Please note however that ipv4.may-fail=no would not prevent the
connection to fail: it would just ensure that to activate the
connection you need the success of the ipv4 method (also if an address
for ipv6 is acquired in the meanwhile).
The fact that an ipv4 connection may fail (also one with dhcp) is a
feature: this would allow for instance to setup multiple connections
with different priorities on the same interface, giving first a try to
the dhcp connection and then falling back to another one with static
ipv4 address or with 802.1x configuration.

If you really want your dhcp connection to keep trying forever the
only viable solution at present seems to be the ipv4.dhcp-timeout
property.
Maybe we could manage to keep trying also with a brand new value to
the ipv4.method... see:
https://bugzilla.redhat.com/show_bug.cgi?id=1350830#c1
Apart from that, there is nothing I would change.

Francesco

> Cheers, Oliver
>
>
>
> _______________________________________________ networkmanager-list
> mailing list networkmanager-list gnome org 
> https://mail.gnome.org/mailman/listinfo/networkmanager-list
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