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Re: Ethernet is not started at boot




On Tue 06 Feb 2018 at 20:23:13 -0500, Michael Stone wrote:

> On Wed, Feb 07, 2018 at 01:16:28AM +0000, Brian wrote:
> > On Tue 06 Feb 2018 at 19:53:16 -0500, Michael Stone wrote:
> > 
> > > On Tue, Feb 06, 2018 at 11:00:12PM +0000, Brian wrote:
> > > > On Tue 06 Feb 2018 at 17:06:36 -0500, Gene Heskett wrote:
> > > > > On Tuesday 06 February 2018 14:07:55 Brian wrote:
> > > > > >
> > > > > > 1. auto enp0s25
> > > > > >                                                  iface enp0s25 inet
> > > > > > static address         192.168.0.202
> > > > > >         netmask         255.255.255.0
> > > > > >         gateway         192.168.0.1
> > > > > >         network         192.168.0.0
> > > > > >
> > > > > > netmask and network are not needed. ifupdown will compute them. Note
> > > > > > there are no examples in interfaces(5) which use these parameters.
> > > > > >
> > > > > You should go and read that man page again.
> > > >
> > > > I didn't have to but I did. A line beginning "netmask" is not required".
> > > 
> > > If you don't specify a netmask it will default to something that was correct
> > > in the 80s and is probably wrong on your network. The "netmask line" isn't
> > > required, but if you don't have a netmask line you should specify the
> > > netmask in the address line (using "ip/netmask" syntax).
> > 
> > Indeed. But a netmask line (while not necessary) doesn't do any harm.
> 
> More than that: either a separate netmask entry or a netmask specified as
> part of the address are almost certainly required for proper operation. It's
> not technically required, but it is practically required.

The changelog says:

  * Calculate netmask internally, so even if a user haven't supplied
    one or have used CIDR notation, hook scripts will have it properly
    specified in IF_NETMASK environment variable.

What is the significance of "...so even if a user haven't supplied ..."?

-- 
Brian.