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Setting up Qemu with a tap interface

Setting up Qemu with a tap interface

There are two parts to networking within QEMU:

  • The virtual network device that is provided to the guest (e.g. a PCI network card).
  • The network backend that interacts with the emulated NIC (e.g. puts packets onto the host's network).

Example: User mode network

User mode networking allows the guest to connect back to the outside world through TCP, UDP etc. ICMP Ping is not allowed. Also connections from host to guest are not allowed unless using port forwarding.

$ qemu-system-i386 -cdrom Core-current.iso -boot d -netdev user,id=mynet0,hostfwd=tcp::8080-:80 -device e1000,netdev=mynet0
-netdev user,id=mynet0,hostfwd=tcp::8080-:80

Create the user mode network backend having id mynet0. Redirect incoming tcp connections on host port 8080 to guest port 80. The syntax is hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport

-device e1000,netdev=mynet0

Create a NIC (model e1000) and connect to mynet0 backend created by the previous parameter

Example: Tap network

TAP network overcomes all of the limitations of user mode networking, but requires a tap to be setup before running qemu. Also qemu must be run with root privileges.

$ sudo qemu-system-i386 -cdrom Core-current.iso -boot d -netdev tap,id=mynet0,ifname=tap0,script=no,downscript=no -device e1000,netdev=mynet0,mac=52:55:00:d1:55:01
-netdev tap,id=mynet0,ifname=tap0,script=no,downscript=no

Create a tap network backend with id mynet0. This will connect to a tap interface tap0 which must be already setup. Do not use any network configuration scripts.

-device e1000,netdev=mynet0,mac=52:55:00:d1:55:01

Create a NIC (model e1000) and connect to mynet0 backend created by the previous parameter. Also specify a mac address for the NIC.

Setup

  • Create a bridge

     brctl addbr br0
    
  • Clear IP of eth0

     ip addr flush dev eth0
    
  • Add eth0 to bridge

     brctl addif br0 eth0
    
  • Create tap interface

     tunctl -t tap0 -u `whoami`
    
  • Add tap0 to bridge

     brctl addif br0 tap0
    
  • Make sure everything is up

     ifconfig eth0 up
     ifconfig tap0 up
     ifconfig br0 up
    
  • Check if properly bridged

     brctl show
    
  • Assign ip to br0

     dhclient -v br0
    

Cleanup

  • Remove tap interface tap0 from bridge br0

    brctl delif br0 tap0
    
  • Delete tap0

    tunctl -d tap0
    
  • Remove eth0 from bridge

    brctl delif br0 eth0
    
  • Bring bridge down

    ifconfig br0 down
    
  • Remove bridge

    brctl delbr br0
    
  • Bring eth0 up

    ifconfig eth0 up
    
  • Check if an IP is assigned to eth0, if not request one

    dhclient -v eth0
    

dhclient - Auto configuration using a DHCP server

  • Release IP

    dhclient -v -r <interface>
    
  • Request IP

    dhclient -v <interface>
    

References

QEMU emulator version 2.5.0 (Debian 1:2.5+dfsg-5ubuntu10.16), Copyright (c) 2003-2008 Fabrice Bellard
usage: qemu-system-i386 [options] [disk_image]
'disk_image' is a raw hard disk image for IDE hard disk 0
Standard options:
-h or -help display this help and exit
-version display version information and exit
-machine [type=]name[,prop[=value][,...]]
selects emulated machine ('-machine help' for list)
property accel=accel1[:accel2[:...]] selects accelerator
supported accelerators are kvm, xen, tcg (default: tcg)
kernel_irqchip=on|off controls accelerated irqchip support
vmport=on|off|auto controls emulation of vmport (default: auto)
kvm_shadow_mem=size of KVM shadow MMU
dump-guest-core=on|off include guest memory in a core dump (default=on)
mem-merge=on|off controls memory merge support (default: on)
iommu=on|off controls emulated Intel IOMMU (VT-d) support (default=off)
igd-passthru=on|off controls IGD GFX passthrough support (default=off)
aes-key-wrap=on|off controls support for AES key wrapping (default=on)
dea-key-wrap=on|off controls support for DEA key wrapping (default=on)
suppress-vmdesc=on|off disables self-describing migration (default=off)
-cpu cpu select CPU ('-cpu help' for list)
-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,sockets=sockets]
set the number of CPUs to 'n' [default=1]
maxcpus= maximum number of total cpus, including
offline CPUs for hotplug, etc
cores= number of CPU cores on one socket
threads= number of threads on one CPU core
sockets= number of discrete sockets in the system
-numa node[,mem=size][,cpus=cpu[-cpu]][,nodeid=node]
-numa node[,memdev=id][,cpus=cpu[-cpu]][,nodeid=node]
-add-fd fd=fd,set=set[,opaque=opaque]
Add 'fd' to fd 'set'
-set group.id.arg=value
set <arg> parameter for item <id> of type <group>
i.e. -set drive.$id.file=/path/to/image
-global driver.property=value
-global driver=driver,property=property,value=value
set a global default for a driver property
-boot [order=drives][,once=drives][,menu=on|off]
[,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]
'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)
'sp_name': the file's name that would be passed to bios as logo picture, if menu=on
'sp_time': the period that splash picture last if menu=on, unit is ms
'rb_timeout': the timeout before guest reboot when boot failed, unit is ms
-m[emory] [size=]megs[,slots=n,maxmem=size]
configure guest RAM
size: initial amount of guest memory
slots: number of hotplug slots (default: none)
maxmem: maximum amount of guest memory (default: none)
NOTE: Some architectures might enforce a specific granularity
-mem-path FILE provide backing storage for guest RAM
-mem-prealloc preallocate guest memory (use with -mem-path)
-k language use keyboard layout (for example 'fr' for French)
-audio-help print list of audio drivers and their options
-soundhw c1,... enable audio support
and only specified sound cards (comma separated list)
use '-soundhw help' to get the list of supported cards
use '-soundhw all' to enable all of them
-balloon none disable balloon device
-balloon virtio[,addr=str]
enable virtio balloon device (default)
-device driver[,prop[=value][,...]]
add device (based on driver)
prop=value,... sets driver properties
use '-device help' to print all possible drivers
use '-device driver,help' to print all possible properties
-name string1[,process=string2][,debug-threads=on|off]
set the name of the guest
string1 sets the window title and string2 the process name (on Linux)
When debug-threads is enabled, individual threads are given a separate name (on Linux)
NOTE: The thread names are for debugging and not a stable API.
-uuid %08x-%04x-%04x-%04x-%012x
specify machine UUID
Block device options:
-fda/-fdb file use 'file' as floppy disk 0/1 image
-hda/-hdb file use 'file' as IDE hard disk 0/1 image
-hdc/-hdd file use 'file' as IDE hard disk 2/3 image
-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)
-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]
[,cyls=c,heads=h,secs=s[,trans=t]][,snapshot=on|off]
[,cache=writethrough|writeback|none|directsync|unsafe][,format=f]
[,serial=s][,addr=A][,rerror=ignore|stop|report]
[,werror=ignore|stop|report|enospc][,id=name][,aio=threads|native]
[,readonly=on|off][,copy-on-read=on|off]
[,discard=ignore|unmap][,detect-zeroes=on|off|unmap]
[[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]
[[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]
[[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]
[[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]
[[,iops_size=is]]
[[,group=g]]
use 'file' as a drive image
-mtdblock file use 'file' as on-board Flash memory image
-sd file use 'file' as SecureDigital card image
-pflash file use 'file' as a parallel flash image
-snapshot write to temporary files instead of disk image files
-hdachs c,h,s[,t]
force hard disk 0 physical geometry and the optional BIOS
translation (t=none or lba) (usually QEMU can guess them)
-fsdev fsdriver,id=id[,path=path,][security_model={mapped-xattr|mapped-file|passthrough|none}]
[,writeout=immediate][,readonly][,socket=socket|sock_fd=sock_fd]
-virtfs local,path=path,mount_tag=tag,security_model=[mapped-xattr|mapped-file|passthrough|none]
[,writeout=immediate][,readonly][,socket=socket|sock_fd=sock_fd]
-virtfs_synth Create synthetic file system image
USB options:
-usb enable the USB driver (will be the default soon)
-usbdevice name add the host or guest USB device 'name'
Display options:
-display sdl[,frame=on|off][,alt_grab=on|off][,ctrl_grab=on|off]
[,window_close=on|off]|curses|none|
gtk[,grab_on_hover=on|off]|
vnc=<display>[,<optargs>]
select display type
-nographic disable graphical output and redirect serial I/Os to console
-curses use a curses/ncurses interface instead of SDL
-no-frame open SDL window without a frame and window decorations
-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)
-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)
-no-quit disable SDL window close capability
-sdl enable SDL
-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]
[,x509-key-file=<file>][,x509-key-password=<file>]
[,x509-cert-file=<file>][,x509-cacert-file=<file>]
[,x509-dh-key-file=<file>][,addr=addr][,ipv4|ipv6|unix]
[,tls-ciphers=<list>]
[,tls-channel=[main|display|cursor|inputs|record|playback]]
[,plaintext-channel=[main|display|cursor|inputs|record|playback]]
[,sasl][,password=<secret>][,disable-ticketing]
[,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]
[,jpeg-wan-compression=[auto|never|always]]
[,zlib-glz-wan-compression=[auto|never|always]]
[,streaming-video=[off|all|filter]][,disable-copy-paste]
[,disable-agent-file-xfer][,agent-mouse=[on|off]]
[,playback-compression=[on|off]][,seamless-migration=[on|off]]
enable spice
at least one of {port, tls-port} is mandatory
-portrait rotate graphical output 90 deg left (only PXA LCD)
-rotate <deg> rotate graphical output some deg left (only PXA LCD)
-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]
select video card type
-full-screen start in full screen
-vnc display start a VNC server on display
1 target only:
-win2k-hack use it when installing Windows 2000 to avoid a disk full bug
-no-fd-bootchk disable boot signature checking for floppy disks
-no-acpi disable ACPI
-no-hpet disable HPET
-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n][,asl_compiler_id=str][,asl_compiler_rev=n][,{data|file}=file1[:file2]...]
ACPI table description
-smbios file=binary
load SMBIOS entry from binary file
-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]
[,uefi=on|off]
specify SMBIOS type 0 fields
-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]
[,uuid=uuid][,sku=str][,family=str]
specify SMBIOS type 1 fields
-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]
[,asset=str][,location=str]
specify SMBIOS type 2 fields
-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]
[,sku=str]
specify SMBIOS type 3 fields
-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]
[,asset=str][,part=str]
specify SMBIOS type 4 fields
-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]
[,asset=str][,part=str][,speed=%d]
specify SMBIOS type 17 fields
Network options:
-netdev user,id=str[,net=addr[/mask]][,host=addr][,restrict=on|off]
[,hostname=host][,dhcpstart=addr][,dns=addr][,dnssearch=domain][,tftp=dir]
[,bootfile=f][,hostfwd=rule][,guestfwd=rule][,smb=dir[,smbserver=addr]]
configure a user mode network backend with ID 'str',
its DHCP server and optional services
-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]
[,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]
[,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]
configure a host TAP network backend with ID 'str'
use network scripts 'file' (default=/etc/qemu-ifup)
to configure it and 'dfile' (default=/etc/qemu-ifdown)
to deconfigure it
use '[down]script=no' to disable script execution
use network helper 'helper' (default=/usr/lib/qemu/qemu-bridge-helper) to
configure it
use 'fd=h' to connect to an already opened TAP interface
use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces
use 'sndbuf=nbytes' to limit the size of the send buffer (the
default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')
use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag
use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition
use vhost=on to enable experimental in kernel accelerator
(only has effect for virtio guests which use MSIX)
use vhostforce=on to force vhost on for non-MSIX virtio guests
use 'vhostfd=h' to connect to an already opened vhost net device
use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices
use 'queues=n' to specify the number of queues to be created for multiqueue TAP
-netdev bridge,id=str[,br=bridge][,helper=helper]
configure a host TAP network backend with ID 'str' that is
connected to a bridge (default=br0)
using the program 'helper (default=/usr/lib/qemu/qemu-bridge-helper)
-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]
[,rxsession=rxsession],txsession=txsession[,ipv6=on/off][,udp=on/off]
[,cookie64=on/off][,counter][,pincounter][,txcookie=txcookie]
[,rxcookie=rxcookie][,offset=offset]
configure a network backend with ID 'str' connected to
an Ethernet over L2TPv3 pseudowire.
Linux kernel 3.3+ as well as most routers can talk
L2TPv3. This transport allows connecting a VM to a VM,
VM to a router and even VM to Host. It is a nearly-universal
standard (RFC3391). Note - this implementation uses static
pre-configured tunnels (same as the Linux kernel).
use 'src=' to specify source address
use 'dst=' to specify destination address
use 'udp=on' to specify udp encapsulation
use 'srcport=' to specify source udp port
use 'dstport=' to specify destination udp port
use 'ipv6=on' to force v6
L2TPv3 uses cookies to prevent misconfiguration as
well as a weak security measure
use 'rxcookie=0x012345678' to specify a rxcookie
use 'txcookie=0x012345678' to specify a txcookie
use 'cookie64=on' to set cookie size to 64 bit, otherwise 32
use 'counter=off' to force a 'cut-down' L2TPv3 with no counter
use 'pincounter=on' to work around broken counter handling in peer
use 'offset=X' to add an extra offset between header and data
-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]
configure a network backend to connect to another network
using a socket connection
-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]
configure a network backend to connect to a multicast maddr and port
use 'localaddr=addr' to specify the host address to send packets from
-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]
configure a network backend to connect to another network
using an UDP tunnel
-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]
configure a vhost-user network, backed by a chardev 'dev'
-netdev hubport,id=str,hubid=n
configure a hub port on QEMU VLAN 'n'
-net nic[,vlan=n][,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]
old way to create a new NIC and connect it to VLAN 'n'
(use the '-device devtype,netdev=str' option if possible instead)
-net dump[,vlan=n][,file=f][,len=n]
dump traffic on vlan 'n' to file 'f' (max n bytes per packet)
-net none use it alone to have zero network devices. If no -net option
is provided, the default is '-net nic -net user'
-net [user|tap|bridge|socket][,vlan=n][,option][,option][,...]
old way to initialize a host network interface
(use the -netdev option if possible instead)
Character device options:
-chardev null,id=id[,mux=on|off]
-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4][,ipv6][,nodelay][,reconnect=seconds]
[,server][,nowait][,telnet][,reconnect=seconds][,mux=on|off] (tcp)
-chardev socket,id=id,path=path[,server][,nowait][,telnet][,reconnect=seconds][,mux=on|off] (unix)
-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]
[,localport=localport][,ipv4][,ipv6][,mux=on|off]
-chardev msmouse,id=id[,mux=on|off]
-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]
[,mux=on|off]
-chardev ringbuf,id=id[,size=size]
-chardev file,id=id,path=path[,mux=on|off]
-chardev pipe,id=id,path=path[,mux=on|off]
-chardev pty,id=id[,mux=on|off]
-chardev stdio,id=id[,mux=on|off][,signal=on|off]
-chardev braille,id=id[,mux=on|off]
-chardev serial,id=id,path=path[,mux=on|off]
-chardev tty,id=id,path=path[,mux=on|off]
-chardev parallel,id=id,path=path[,mux=on|off]
-chardev parport,id=id,path=path[,mux=on|off]
-chardev spicevmc,id=id,name=name[,debug=debug]
-chardev spiceport,id=id,name=name[,debug=debug]
Device URL Syntax:
-iscsi [user=user][,password=password]
[,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE
[,initiator-name=initiator-iqn][,id=target-iqn]
[,timeout=timeout]
iSCSI session parameters
Bluetooth(R) options:
-bt hci,null dumb bluetooth HCI - doesn't respond to commands
-bt hci,host[:id]
use host's HCI with the given name
-bt hci[,vlan=n]
emulate a standard HCI in virtual scatternet 'n'
-bt vhci[,vlan=n]
add host computer to virtual scatternet 'n' using VHCI
-bt device:dev[,vlan=n]
emulate a bluetooth device 'dev' in scatternet 'n'
TPM device options:
-tpmdev passthrough,id=id[,path=path][,cancel-path=path]
use path to provide path to a character device; default is /dev/tpm0
use cancel-path to provide path to TPM's cancel sysfs entry; if
not provided it will be searched for in /sys/class/misc/tpm?/device
Linux/Multiboot boot specific:
-kernel bzImage use 'bzImage' as kernel image
-append cmdline use 'cmdline' as kernel command line
-initrd file use 'file' as initial ram disk
-dtb file use 'file' as device tree image
Debug/Expert options:
-fw_cfg [name=]<name>,file=<file>
add named fw_cfg entry from file
-fw_cfg [name=]<name>,string=<str>
add named fw_cfg entry from string
-serial dev redirect the serial port to char device 'dev'
-parallel dev redirect the parallel port to char device 'dev'
-monitor dev redirect the monitor to char device 'dev'
-qmp dev like -monitor but opens in 'control' mode
-qmp-pretty dev like -qmp but uses pretty JSON formatting
-mon [chardev=]name[,mode=readline|control][,default]
-debugcon dev redirect the debug console to char device 'dev'
-pidfile file write PID to 'file'
-singlestep always run in singlestep mode
-S freeze CPU at startup (use 'c' to start execution)
-realtime [mlock=on|off]
run qemu with realtime features
mlock=on|off controls mlock support (default: on)
-gdb dev wait for gdb connection on 'dev'
-s shorthand for -gdb tcp::1234
-d item1,... enable logging of specified items (use '-d help' for a list of log items)
-D logfile output log to logfile (default stderr)
-L path set the directory for the BIOS, VGA BIOS and keymaps
-bios file set the filename for the BIOS
-enable-kvm enable KVM full virtualization support
-xen-domid id specify xen guest domain id
-xen-create create domain using xen hypercalls, bypassing xend
warning: should not be used when xend is in use
-xen-attach attach to existing xen domain
xend will use this when starting QEMU
-no-reboot exit instead of rebooting
-no-shutdown stop before shutdown
-loadvm [tag|id]
start right away with a saved state (loadvm in monitor)
-daemonize daemonize QEMU after initializing
-option-rom rom load a file, rom, into the option ROM space
-rtc [base=utc|localtime|date][,clock=host|rt|vm][,driftfix=none|slew]
set the RTC base and clock, enable drift fix for clock ticks (x86 only)
-icount [shift=N|auto][,align=on|off][,sleep=no,rr=record|replay,rrfile=<filename>]
enable virtual instruction counter with 2^N clock ticks per
instruction, enable aligning the host and virtual clocks
or disable real time cpu sleeping
-watchdog model
enable virtual hardware watchdog [default=none]
-watchdog-action reset|shutdown|poweroff|pause|debug|none
action when watchdog fires [default=reset]
-echr chr set terminal escape character instead of ctrl-a
-virtioconsole c
set virtio console
-show-cursor show cursor
-tb-size n set TB size
-incoming tcp:[host]:port[,to=maxport][,ipv4][,ipv6]
-incoming rdma:host:port[,ipv4][,ipv6]
-incoming unix:socketpath
prepare for incoming migration, listen on
specified protocol and socket address
-incoming fd:fd
-incoming exec:cmdline
accept incoming migration on given file descriptor
or from given external command
-incoming defer
wait for the URI to be specified via migrate_incoming
-nodefaults don't create default devices
-chroot dir chroot to dir just before starting the VM
-runas user change to user id user just before starting the VM
-sandbox <arg> Enable seccomp mode 2 system call filter (default 'off').
-readconfig <file>
-writeconfig <file>
read/write config file
-nodefconfig
do not load default config files at startup
-no-user-config
do not load user-provided config files at startup
-trace [events=<file>][,file=<file>]
specify tracing options
-enable-fips enable FIPS 140-2 compliance
-msg timestamp[=on|off]
change the format of messages
on|off controls leading timestamps (default:on)
-dump-vmstate <file>
Output vmstate information in JSON format to file.
Use the scripts/vmstate-static-checker.py file to
check for possible regressions in migration code
by comparing two such vmstate dumps.
Generic object creation
-object TYPENAME[,PROP1=VALUE1,...]
create a new object of type TYPENAME setting properties
in the order they are specified. Note that the 'id'
property must be set. These objects are placed in the
'/objects' path.
During emulation, the following keys are useful:
ctrl-alt-f toggle full screen
ctrl-alt-n switch to virtual console 'n'
ctrl-alt toggle mouse and keyboard grab
When using -nographic, press 'ctrl-a h' to get some help.
@ChrisLucas29

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@ChrisLucas29 ChrisLucas29 commented Sep 27, 2018

Hey there,
I'm having issues implementing a connection type to my virtual machine. I'm not very familiar with Qemu ( I usually use vmware). What are the equivalent to NAT, bridged and host-only on qemu? How do you implemented them?

Chris

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@extremecoders-re extremecoders-re commented Oct 21, 2018

@MagicVin

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@MagicVin MagicVin commented Dec 11, 2018

Hey there,
I'm having issues implementing a connection type to my virtual machine. I'm not very familiar with Qemu ( I usually use vmware). What are the equivalent to NAT, bridged and host-only on qemu? How do you implemented them?

Chris

You can see the virt-manager(libvirt tool) which usage is likes the vmware.

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@Marietto2008 Marietto2008 commented May 6, 2020

Hello.

I've installed ubuntu 20.04 on WSL2 and I started a VM with qemu and kvm,running mac os x as guest os. It works great,except for the configuration of the net. Infact it is not able to connect to internet. Sometime from WSL I get a 192.x.x.x ip number,like :

192.168.69.65 ; 192.168.71.185 ; 192.168.73.223 ; 192.168.69.33 ; 192.168.100.101

sometime I get a 172.x.x.x ip address,like : 172.22.250.54 ; 172.22.253.128 ; 172.21.138.120 ; 172.22.88.142.

The vEthernet (WSL) adapter on Windows 10 is configued like this : 172.26.80.1 as IP address,subnet mask = 255.255.240.0

I have created a bridge in WIndows 10,between my Intel ethernet adapter and the tap0 / Tap-windows. It's IP is 192.168.1.6 ; subnet mask = 255.255.255.0 ; gateway = 192.169.1.1 ; dns primary = 8.8.8.8

I have configured WSL like it is explained,but it didn't work. Check below what happens :

root@DESKTOP-N9UN2H3:/mnt/c/Android/sdk/platform-tools# brctl addbr br0
root@DESKTOP-N9UN2H3:/mnt/c/Android/sdk/platform-tools# ip addr flush dev eth0
root@DESKTOP-N9UN2H3:/mnt/c/Android/sdk/platform-tools# brctl addif br0 eth0

root@DESKTOP-N9UN2H3:/mnt/c/Android/sdk/platform-tools# tunctl -t tap0 -u root
Set 'tap0' persistent and owned by uid 0

root@DESKTOP-N9UN2H3:/mnt/c/Android/sdk/platform-tools# brctl addif br0 tap0
root@DESKTOP-N9UN2H3:/mnt/c/Android/sdk/platform-tools# ifconfig eth0 up
root@DESKTOP-N9UN2H3:/mnt/c/Android/sdk/platform-tools# ifconfig tap0 up
root@DESKTOP-N9UN2H3:/mnt/c/Android/sdk/platform-tools# ifconfig br0 up

root@DESKTOP-N9UN2H3:/mnt/c/Android/sdk/platform-tools# brctl show
bridge name bridge id STP enabled interfaces
br0 8000.00155d99cfa4 no eth0
tap0

root@DESKTOP-N9UN2H3:/mnt/c/Android/sdk/platform-tools# dhclient -v br0

Internet Systems Consortium DHCP Client 4.4.1
Copyright 2004-2018 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/br0/00:15:5d:99:cf:a4
Sending on LPF/br0/00:15:5d:99:cf:a4
Sending on Socket/fallback
DHCPDISCOVER on br0 to 255.255.255.255 port 67 interval 3 (xid=0xbbd3b615)
DHCPDISCOVER on br0 to 255.255.255.255 port 67 interval 8 (xid=0xbbd3b615)
DHCPDISCOVER on br0 to 255.255.255.255 port 67 interval 12 (xid=0xbbd3b615)
DHCPDISCOVER on br0 to 255.255.255.255 port 67 interval 11 (xid=0xbbd3b615)

root@DESKTOP-N9UN2H3:/mnt/c/Android/sdk/platform-tools# ifconfig

br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet6 fe80::215:5dff:fe99:cfa4 prefixlen 64 scopeid 0x20
ether 00:15:5d:99:cf:a4 txqueuelen 1000 (Ethernet)
RX packets 172 bytes 43127 (43.1 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 16 bytes 2304 (2.3 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
ether 00:15:5d:99:cf:a4 txqueuelen 1000 (Ethernet)
RX packets 543 bytes 121055 (121.0 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 28 bytes 3280 (3.2 KB)
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
loop txqueuelen 1000 (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

tap0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
ether 46:88:cb:85:5f:9e txqueuelen 1000 (Ethernet)
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

root@DESKTOP-N9UN2H3:/mnt/c/Android/sdk/platform-tools# ping www.google.it
ping: www.google.it: Name or service not known

I think IPv4 issue can be solved with configuring DHCP, but I don't know how to do that. I dont know why after removing address from eth0, which had an ipv4 address, and creating a bridge,it becomes no ipv4.

@nevilad

@CristianPi

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@CristianPi CristianPi commented Feb 8, 2021

does not work on fedora 33, the vm has a weird ip address without internet access.
Anything special i need to do?

config

#BRIDGED NETWORKING
 brctl addbr br1
 ip addr flush dev eno1
 brctl addif br1 eno1
 tunctl -t tap0 -u `whoami`
 brctl addif br1 tap0
 ifconfig eno1 up
 ifconfig tap0 up
 ifconfig br1 up
 brctl show
 dhclient -v br1
 dhclient -v tap0
NET="-netdev tap,id=net0,ifname=tap0,script=no,downscript=no"
#NET="-netdev user,id=net0 -device rtl8139,netdev=net0"
#NET="-netdev tap,id=net0,ifname=tap0,netdev=net0"

#NDV="-device vmxnet3,netdev=net0,id=net0,mac=52:54:00:c9:18:27"
#NDV="-device rtl8139,netdev=net0,id=net0,mac=52:54:00:c9:18:27"
NVD= "-device e1000,netdev=net0,mac=52:54:00:c9:18:27"
#NDV= ""

extra=

# CD-ROM boot:
extra="-boot d"
extra="${extra} -drive file=Win10_20H2_EnglishInternational_x64.iso,media=cdrom"
#extra="${extra} -drive file=/home/swarren/shared/archive/Windows/virtio-win-0.1.126.iso,media=cdrom"

qemu-system-x86_64 \
    -enable-kvm \
    -m 12G \
    -machine q35,accel=kvm \
    -smp 16,cores=8 \
    -cpu Penryn,vendor=GenuineIntel,kvm=on,+sse3,+sse4.2,+aes,+xsave,+avx,+xsaveopt,+xsavec,+xgetbv1,+avx2,+bmi2,+smep,+bmi1,+fma,+movbe,+invtsc \
    -device isa-applesmc,osk="$OSK" \
    -smbios type=2 \
    -vga qxl \
    -device ich9-intel-hda -device hda-output \
    -usb -device usb-kbd -device usb-mouse \
    $NET \
    $NDV \
    -device ich9-ahci,id=sata \
    -drive id=SystemDisk,if=none,file=MyDisk.qcow2 \
    -device ide-hd,bus=sata.4,drive=SystemDisk \
    -device pcie-root-port,bus=pcie.0,multifunction=on,port=1,chassis=1,id=port.1 \
    -device vfio-pci,host=28:00.0,bus=port.1,multifunction=on,romfile=./Gigabyte.RX5708GB.8192.180505.rom \
    -device vfio-pci,host=28:00.1,bus=port.1 \
    $extra

output

Set 'tap0' persistent and owned by uid 0
bridge name	bridge id		STP enabled	interfaces
br1		8000.ba6486f33778	no		eno1
							tap0
virbr0		8000.5254009de47c	yes		virbr0-nic
Internet Systems Consortium DHCP Client 4.4.2b1
Copyright 2004-2019 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/br1/ba:64:86:f3:37:78
Sending on   LPF/br1/ba:64:86:f3:37:78
Sending on   Socket/fallback
DHCPREQUEST for 192.168.1.167 on br1 to 255.255.255.255 port 67 (xid=0xb6f59c41)
DHCPACK of 192.168.1.167 from 192.168.1.1 (xid=0xb6f59c41)
bound to 192.168.1.167 -- renewal in 6243 seconds.
dhclient(4522) is already running - exiting. 
@extremecoders-re

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@extremecoders-re extremecoders-re commented Feb 9, 2021

@CristianPi You can try with user mode emulation which doesn't require a tap to be setup. Also would recommend to use virt-manager to set up the VM's which would take care of setting the correct options.

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