Re: Creating a tap device.

["Alexander V. Makartsev" <avbetev@gmail.com>]

On 14.03.2021 09:55, peter@easthope.ca wrote:

> My previous message was meant for another list.  Apology for the 
> disturbance.
>
> I've set aside the instructions for qemu.  Trying to understand how a 
> tap device is created.  "man ip" has minimal explanation of "ip tuntap".
>
> https://stackoverflow.com/questions/15626088/tap-interfaces-and-dev-net-tun-device-using-ip-tuntap-command
> prompts this.
>
> peter@joule:/home/peter$ sudo ip tuntap add mode tap tap0
> [sudo] password for peter:
> open: No such file or directory
>
> peter@joule:/home/peter$ ls -ld /dev/tu*
> lrwxrwxrwx 1 root root 12 Mar 13 07:34 /dev/tun -> /dev/net/tun
>
> Can anyone succeed to create a tap device using ip in Debian 10?
>
> Thx,            ... P.
>
>     
    I can.
    $ sudo ip tuntap add mode tap ether0-tap
      $ sudo ip tuntap list
      virbr1-nic: tap persist
      ether0-tap: tap persist
      $ sudo ip link list
      1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state
      UNKNOWN mode DEFAULT group default qlen 1000
          link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
      2: ether0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
      pfifo_fast state UP mode DEFAULT group default qlen 1000
          link/ether 1c:1b:0d:01:02:03 brd ff:ff:ff:ff:ff:ff
      3: virbr1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500
      qdisc noqueue state DOWN mode DEFAULT group default qlen 1000
          link/ether 52:54:00:01:02:03 brd ff:ff:ff:ff:ff:ff
      4: virbr1-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc
      pfifo_fast master virbr1 state DOWN mode DEFAULT group default
      qlen 1000
          link/ether 52:54:00:01:02:03 brd ff:ff:ff:ff:ff:ff
      5: ether0-tap: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
      state DOWN mode DEFAULT group default qlen 1000
          link/ether 7e:63:1e:70:cf:c2 brd ff:ff:ff:ff:ff:ff
      $ sudo ip tuntap del mode tap ether0-tap
      $ sudo ip tuntap list
      virbr1-nic: tap persist
    
    But it wasn't creating a device with chosen name anywhere under
    "/dev" or "/dev/net/".
    I believe, "/dev/net/tun" device is created when "tun" kernel module
    is inserted.
    
-- 
With kindest regards, Alexander.

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