Hvad har de 5 Raspberry Pi systemer tilfælles ?

De har alle den samme MAC addresse 00:e0:4c:53:44:58

Derudover er det den billigste ethernet/usb/hub på Ebay $3.25, og sikkert også den dårligste.

$ lsusb -d 0fe6:9700 -v

Bus 001 Device 004: ID 0fe6:9700 Kontron (Industrial Computer Source / ICS Advent) DM9601 Fast Ethernet Adapter
Couldn't open device, some information will be missing
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            0 (Defined at Interface level)
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0        64
  idVendor           0x0fe6 Kontron (Industrial Computer Source / ICS Advent)
  idProduct          0x9700 DM9601 Fast Ethernet Adapter
  bcdDevice            1.01
  iManufacturer           0 
  iProduct                2 
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           39
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              120mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           3
      bInterfaceClass         0 (Defined at Interface level)
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 
      iInterface              0 
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x02  EP 2 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0040  1x 64 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval               1

Der er tale om en USB1.1 enhed, som man brugte i det forrige årtusinde. USB1.1 har en maximal hastighed på 12 MBit/sec, som man ser i klumber af maximalt 64 bytes.  Men til mange ting er det jo nok.  Så vi skal blot have fixet problemet med MAC-addressen.  Det kan klares med en lille udev-rule

$ cat /etc/udev/rules.d/99-dm9601.rules 
# set MAC to hostbased MAC as on Raspberry pi 3
ACTION=="add|move", SUBSYSTEM=="net", SUBSYSTEMS=="usb", ATTR{address}=="00:e0:4c:53:44:58", IMPORT{program}="/usr/local/sbin/fix_mac_00e04c534458.sh", ENV{NM_UNMANAGED}="1"

Der kalder et script

$ cat /usr/local/sbin/fix_mac_00e04c534458.sh 
#!/bin/bash
# raspberry pi 3 has MAC b8:27:eb:..:..:.. the last 3 bytes is the last 3 bytes of serial no.
SERIAL=($(sed -n '/^Serial/{s/.* //;p}' /proc/cpuinfo | fold -w2))
if  [ ${#SERIAL[@]} != 8 ]; then
#	echo this is not a Raspberry Pi, use 8 lower bytes from machine-id
	SERIAL=($(fold -w2 /etc/machine-id | tail -8))
fi
NEW_MAC=b8:27:eb:${SERIAL[5]}:${SERIAL[6]}:${SERIAL[7]}
if [ x$INTERFACE != x ]; then
	/bin/ip link set dev $INTERFACE address $NEW_MAC
fi
echo "ATTR{address}==\"$NEW_MAC\""

Jeg vil dog anbefale at man undgår disse usb/ethernet/hub og i stedet får fat i in 4 ports USB-hub (ebay $1) og en USB-WiFi (ebay $1.75) så har man en meget hurtigere løsning der bruger meget mindre strøm, og så er det billigere.

Men jeg er allerede blevet snydt.