Web lists-archives.com

Re: Ethernet is not started at boot




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.

Mike Stone