Re: Set the MTU on the interface

[Pascal Hambourg <pascal@plouf.fr.eu.org>]

Le 30/07/2018 à 16:23, Dan Purgert a écrit :
> Алексей wrote:
> > I need an advice about how can I set the MTU on the interface which is
> > not in fact configured. So to explain in more detail:
> >
> > I have a debian box acting as a router and it has interface let's say
> > eth0. Eth0 itself doesn't have any IP configuration, all IP
> > configuration and routing is done on vlan interfaces bound to eth0. I
> > need to route jumbo frames so I need to set the MTU on vlan interfaces
> > to 9000 and consequently I need to set MTU to 9000 on the physical
> > eth0 also. However, as i have only one line for eth0 in
> > /etc/network/interfaces:
> >
> > auto eth0

> So then define at least that component of eth0.  No need for an IP
> address / gateway / etc.


"auto" alone does not define any interface configuration. You need an 
"iface" statement to be able the set the mtu option. And the iface 
statement requires an address family and method. The suitable method 
here is "manual". The address family may be inet or inet6.

auto eth0
iface eth0 inet manual
mtu 9000