User mode linux eth0 connected to host tap ethernet device not coming up

I am trying to setup the network between UML instance running on ubuntu as host. UML--eth0-(192.168.0.254) ----------------tap0--(192.168.0.253)--VM But, I am not able to bring the eth0 device in **UP** state, even after configuring an ip address. UML : [root@localhost ~]# ifconfig -a eth0: flags=4098 mtu 1500 inet 192.168.0.254 netmask 255.255.255.0 broadcast 192.168.0.255 ether fa:df:23:a2:22:4b 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 device interrupt 5 lo: flags=73 mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 loop txqueuelen 1 (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 As you can see, eth0 status is only broadcast and multicast but not up. However, tap0 on VM side is up and running. Host VM vm@vm:/dev/net$ ifconfig tap0 tap0 Link encap:Ethernet HWaddr 96:e1:8c:c9:09:54 inet addr:192.168.0.253 Bcast:192.168.0.255 Mask:255.255.255.0 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) I am logged in as a root, even then I am not permitted to trigger the command below. [root@localhost ~]# ifconfig eth0 up SIOCSIFFLAGS: Operation not permitted [root@localhost ~]# ip link set eth0 up RTNETLINK answers: Operation not permitted