Hi there, I've installed a new KVM-Server. The routing in all instances are only working after "arp -s ip_of_router mac_of_router" Server: CentOS7, KVM Clients: CentOS6 and Fedora 21 What going wrong? [root at bgstkvmlr01 ~]# ifconfig bond0: flags=5187<UP,BROADCAST,RUNNING,MASTER,MULTICAST> mtu 1500 inet6 fe80::3ed9:2bff:fe0b:c706 prefixlen 64 scopeid 0x20<link> ether 3c:d9:2b:0b:c7:06 txqueuelen 0 (Ethernet) RX packets 7341811 bytes 9977559369 (9.2 GiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 2649574 bytes 3041071431 (2.8 GiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 10.20.91.233 netmask 255.255.255.0 broadcast 10.20.91.255 inet6 fe80::3ed9:2bff:fe0b:c706 prefixlen 64 scopeid 0x20<link> ether 3c:d9:2b:0b:c7:06 txqueuelen 0 (Ethernet) RX packets 502795 bytes 41156803 (39.2 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 404863 bytes 2871651286 (2.6 GiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 enp3s0f0: flags=6211<UP,BROADCAST,RUNNING,SLAVE,MULTICAST> mtu 1500 ether 3c:d9:2b:0b:c7:06 txqueuelen 1000 (Ethernet) RX packets 7318606 bytes 9975484026 (9.2 GiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 2649122 bytes 3041013575 (2.8 GiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 enp3s0f1: flags=6211<UP,BROADCAST,RUNNING,SLAVE,MULTICAST> mtu 1500 ether 3c:d9:2b:0b:c7:06 txqueuelen 1000 (Ethernet) RX packets 23205 bytes 2075343 (1.9 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 452 bytes 57856 (56.5 KiB) 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<host> loop txqueuelen 0 (Lokale Schleife) RX packets 587461 bytes 3015361475 (2.8 GiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 587461 bytes 3015361475 (2.8 GiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 inet 192.168.122.1 netmask 255.255.255.0 broadcast 192.168.122.255 ether 52:54:00:04:a7:50 txqueuelen 0 (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 vnet0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet6 fe80::fc54:ff:fe63:59c4 prefixlen 64 scopeid 0x20<link> ether fe:54:00:63:59:c4 txqueuelen 500 (Ethernet) RX packets 362 bytes 29416 (28.7 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 3751 bytes 310945 (303.6 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 vnet1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet6 fe80::fc54:ff:fea4:7493 prefixlen 64 scopeid 0x20<link> ether fe:54:00:a4:74:93 txqueuelen 500 (Ethernet) RX packets 594280 bytes 54135245 (51.6 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 6887388 bytes 9904127165 (9.2 GiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 [root at bgstkvmlr01 ~]# route -n Kernel IP Routentabelle Ziel Router Genmask Flags Metric Ref Use Iface 0.0.0.0 10.20.91.1 0.0.0.0 UG 0 0 0 br0 10.20.91.0 0.0.0.0 255.255.255.0 U 0 0 0 br0 169.254.0.0 0.0.0.0 255.255.0.0 U 1011 0 0 br0 192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0 [root at bgstkvmlr01 ~]# Mit freundlichen Grüßen / Kind regards Mr. Andreas Reschke MAHLE International GmbH Unix/Linux-Administration (FIG5.1) Pragstr. 26 - 46, 70376 Stuttgart, Germany Phone: +49 711 501-47598, Fax: +49 711 501-44 47598 Mobile: 0173-3197397 andreas.reschke at mahle.com, http://www.mahle.com MAHLE International GmbH, Location: Stuttgart, Registered: Amtsgericht Stuttgart, HRB 16413 Management Board: Prof. Dr. Heinz K. Junker, Arnd Franz, Michael Frick, Michael Glowatzki