What's wrong with my Xen bridge configuration

I'm on Debian 9 (stretch): $ cat /proc/version Linux version 4.9.0-3-amd64 (debian-kernel@lists.debian.org) (gcc version 6.3.0 20170516 (Debian 6.3.0-18) ) #1 SMP Debian 4.9.30-2+deb9u5 (2017-09-19) I'm trying to setup a Xen guest. I have installed Xen and now working on a Dom-0: sudo xl list Name ID Mem VCPUs State Time(s) Domain-0 0 7881 4 r----- 213.2 $ sudo xl info host : myserver release : 4.9.0-3-amd64 version : #1 SMP Debian 4.9.30-2+deb9u5 (2017-09-19) machine : x86_64 nr_cpus : 4 max_cpu_id : 3 nr_nodes : 1 cores_per_socket : 4 threads_per_core : 1 cpu_mhz : 3092 hw_caps : b7ebfbff:17bae3ff:28100800:00000001:00000001:00000000:00000000:00000100 virt_caps : hvm total_memory : 8103 free_memory : 128 sharing_freed_memory : 0 sharing_used_memory : 0 outstanding_claims : 0 free_cpus : 0 xen_major : 4 xen_minor : 8 xen_extra : .5 xen_version : 4.8.5 xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64 xen_scheduler : credit xen_pagesize : 4096 platform_params : virt_start=0xffff800000000000 xen_changeset : xen_commandline : placeholder cc_compiler : gcc (Debian 6.3.0-18+deb9u1) 6.3.0 20170516 cc_compile_by : ijackson cc_compile_domain : chiark.greenend.org.uk cc_compile_date : Fri Jan 11 18:02:57 UTC 2019 build_id : 9a71c39470d087c0c9fa0d33c04d985ea08aaa04 xend_config_format : 4 Now I'm trying to setup a bridge. I'm following the instructions in https://wiki.xenproject.org/wiki/Xen_Project_Beginners_Guide My configuration file is: $ cat /etc/network/interfaces # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). source /etc/network/interfaces.d/* # The loopback network interface auto lo iface lo inet loopback auto eth0 iface eth0 inet manual auto xenbr0 iface xenbr0 inet dhcp bridge_ports eth0 If I run sudo service networking restart it takes more than a minute. Then the state of the bridge is strange: $ sudo brctl show bridge name bridge id STP enabled interfaces xenbr0 8000.000000000000 no The bridge has no real id and is not enabled. I tried several different configurations for /etc/network/interfaces all of them failed. Any ideas, why I can't setup a xen bridge? **Edit:** After the comment of @A.B and the answer of @user337916 I added the line auto eth0 into my configuration The answers to the follwoing commands are very confusing: sudo brctl addif xenbr0 eth0 interface eth0 does not exist! sudo ifup -v eth0 ifup: interface eth0 already configured How is it possible, that something that _does not exist_ can be _already configured_?. Here is another output: sudo ip link show 1: lo: mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: enp4s0: mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 14:da:e9:dd:ad:93 brd ff:ff:ff:ff:ff:ff 4: xenbr0: mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/ether 3a:d9:57:ac:9a:7c brd ff:ff:ff:ff:ff:ff