Can't change the mtu of OSX host vboxnet interface

[kiorky_]

Hi, i'm trying to change the mtu settings to activate jumbo frames

No problem on guest, i can set to whatever value.

But on host, either with ifconfig or networksetup, i can't:

bash-3.2$ sudo ifconfig vboxnet6  mtu 9000
ifconfig: ioctl (set mtu): Operation not supported on socket
bash-3.2$ sudo networksetup -setMTU vboxnet6 9000
Could not find hardware port or device named vboxnet6.
** Error: The parameters were not valid.
bash-3.2$ 

versions

bash-3.2$ VBoxManage --version
4.3.6r91406
bash-3.2$ uname -ar
Darwin ***.fr 12.5.0 Darwin Kernel Version 12.5.0: Sun Sep 29 13:33:47 PDT 2013; root:xnu-2050.48.12~1/RELEASE_X86_64 x86_64

[kiorky_]

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
        options=3<RXCSUM,TXCSUM>
        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 
        inet 127.0.0.1 netmask 0xff000000 
        inet6 ::1 prefixlen 128 
gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280
stf0: flags=0<> mtu 1280
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=2b<RXCSUM,TXCSUM,VLAN_HWTAGGING,TSO4>
        ether 10:9a:dd:46:0b:2f 
        media: autoselect (none)
        status: inactive
en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        ether c8:bc:c8:e8:82:da 
        inet6 fe80::cabc:c8ff:fee8:82da%en1 prefixlen 64 scopeid 0x5 
        inet 192.168.1.25 netmask 0xffffff00 broadcast 192.168.1.255
        media: autoselect
        status: active
p2p0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 2304
        ether 0a:bc:c8:e8:82:da 
        media: autoselect
        status: inactive
fw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 4078
        lladdr dc:2b:61:ff:fe:ee:d0:10 
        media: autoselect <full-duplex>
        status: inactive
vboxnet1: flags=8842<BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        ether 0a:00:27:00:00:01 
vboxnet2: flags=8842<BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        ether 0a:00:27:00:00:02 
vboxnet3: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        ether 0a:00:27:00:00:03 
        inet 10.1.4.1 netmask 0xff000000 broadcast 10.255.255.255
vboxnet4: flags=8842<BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        ether 0a:00:27:00:00:04 
vboxnet5: flags=8842<BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        ether 0a:00:27:00:00:05 
vboxnet6: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        ether 0a:00:27:00:00:06 
        inet 10.1.6.1 netmask 0xff000000 broadcast 10.255.255.255
bash-3.2$ 

bash-3.2$ netstat -nr
Routing tables

Internet:
Destination        Gateway            Flags        Refs      Use   Netif Expire
default            192.168.1.254      UGSc          194        3     en1
10                 link#13            UC              3        0 vboxnet
10.1.6.43          8:0:27:d0:4d:3f    UHLWIi          1       42 vboxnet   1112
10.255.255.255     ff:ff:ff:ff:ff:ff  UHLWbI          0       18 vboxnet
127                127.0.0.1          UCS             0        0     lo0
127.0.0.1          127.0.0.1          UH              7     2931     lo0
169.254            link#5             UCS             0        0     en1
172.31/24          10.1.6.43          UGSc            0        0     en1
192.168.1          link#5             UCS             7        0     en1
192.168.1.11       0:25:bc:e4:c3:de   UHLWIi          0        1     en1    838
192.168.1.25       127.0.0.1          UHS             0        0     lo0
192.168.1.39       0:40:95:33:be:d4   UHLWIi          0       87     en1   1197
192.168.1.63       d8:a2:5e:25:f3:7d  UHLWIi          0        0     en1    746
192.168.1.80       5c:59:48:20:2b:4b  UHLWIi          0        0     en1
192.168.1.87       10:bf:48:be:51:c3  UHLWIi          2      608     en1   1032
192.168.1.254      80:18:a7:ad:2b:9   UHLWIir       195      685     en1   1192
192.168.1.255      ff:ff:ff:ff:ff:ff  UHLWbI          0       46     en1

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.