dhcpcd-discuss

On 2019-02-08.11:23, Roy Marples wrote:
> Hi Scott
> 
> On 08/02/2019 11:04, Scott Leggett wrote:
> > There's a bug report in Debian[0] that I can reproduce in dhcpcd 7.1.0.
> > Essentially, setting a static interface_mtu doesn't seem to work as
> > expected, though I am not sure if this configuration is even supported?
> > 
> > Here's the interface configuration snippet - note the third line:
> > 
> >      interface ens3
> >      noipv6rs
> >      static interface_mtu=1400
> >      static ip_address=192.168.122.9/24
> >      static routers=192.168.122.1
> >      static domain_name_servers=192.168.122.1
> > 
> > And here's the resulting interface - mtu 1500, when I would have
> > expected 1400:
> > 
> >      2: ens3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
> >          link/ether 52:54:00:ba:4e:d6 brd ff:ff:ff:ff:ff:ff
> >          inet 192.168.122.9/24 brd 192.168.122.255 scope global noprefixroute ens3
> >             valid_lft forever preferred_lft forever
> >          inet6 fe80::6486:7fbd:bf43:e57e/64 scope link
> >             valid_lft forever preferred_lft forever
> > 
> > Is there a bug here, is the configuration wrong, or is this simply not
> > supported?
> 
> This is supported, but not quite how you expect.
> MTU is now set per route rather than for the whole interface, so you can
> have a larger MTU for IPv6 than for IPv4.
> 
> Check output with `ip r`

Hi Roy,

That was it - thanks for the very quick response!

    default via 192.168.122.1 dev ens3 src 192.168.122.9 metric 202 mtu 1400 
    192.168.122.0/24 dev ens3 proto dhcp scope link src 192.168.122.9 metric 202 mtu 1400 

-- 
Regards,
Scott Leggett.

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