[systemd-devel] networkd link file not setting MTU

[Tom Gundersen]

Hi Ian,

Did you try to reboot? Note that .link files are applied by udev (so
usually during early boot). You can override their settings from
.network files in some cases (at least with current git you can).

I was not able to reproduce here (with git). "journalctl -b -u
systemd-udevd" may contain some hints if you can still reproduce when
rebooting.

Cheers,

Tom

On Wed, Jan 21, 2015 at 12:48 AM, Ian Pilcher <arequipeno at gmail.com> wrote:
> I am trying to use systemd-networkd on Fedora 21, and I haven't been
> able to get it to set the MTU of an interface correctly:
>
> [root at localhost network]# cat eth0.link
> [Match]
> MACAddress=52:54:00:d8:3d:3e
>
> [Link]
> MTUBytes=8996
> [root at localhost network]#
>
> [root at localhost network]# cat eth0.network
> [Match]
> MACAddress=52:54:00:d8:3d:3e
>
> [Network]
> DHCP=yes
>
> [root at localhost network]# ifconfig
> eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
>         inet 172.31.253.166  netmask 255.255.255.0  broadcast 172.31.253.255
>         inet6 fe80::5054:ff:fed8:3d3e  prefixlen 64  scopeid 0x20<link>
>         ether 52:54:00:d8:3d:3e  txqueuelen 1000  (Ethernet)
>         RX packets 389  bytes 35608 (34.7 KiB)
>         RX errors 0  dropped 0  overruns 0  frame 0
>         TX packets 245  bytes 28600 (27.9 KiB)
>         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
>
> lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
>         inet 127.0.0.1  netmask 255.0.0.0
>         inet6 ::1  prefixlen 128  scopeid 0x10<host>
>         loop  txqueuelen 0  (Local Loopback)
>         RX packets 0  bytes 0 (0.0 B)
>         RX errors 0  dropped 0  overruns 0  frame 0
>         TX packets 0  bytes 0 (0.0 B)
>         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
>
> As you can see, the MTU is not being set, although setting it manually
> works fine:
>
> [root at localhost network]# ifconfig eth0 mtu 8996
> [root at localhost network]# ifconfig eth0
> eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 8996
>         inet 172.31.253.166  netmask 255.255.255.0  broadcast 172.31.253.255
>         inet6 fe80::5054:ff:fed8:3d3e  prefixlen 64  scopeid 0x20<link>
>         ether 52:54:00:d8:3d:3e  txqueuelen 1000  (Ethernet)
>         RX packets 586  bytes 51538 (50.3 KiB)
>         RX errors 0  dropped 0  overruns 0  frame 0
>         TX packets 288  bytes 33908 (33.1 KiB)
>         TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
>
> Any idea what I'm missing?
>
> --
> ========================================================================
> Ian Pilcher                                         arequipeno at gmail.com
> -------- "I grew up before Mark Zuckerberg invented friendship" --------
> ========================================================================
>
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