Hello /etc/sysconfig/network-scripts/ifcfg-eth0 looks like this: # Intel Corporation 82545EM Gigabit Ethernet Controller (Copper) TYPE=Ethernet NAME=eth0 NM_CONTROLLED=no IPV4_FAILURE_FATAL=yes UUID=cc2635ff-3c14-48ba-b19a-84c5b9d36a9d ONBOOT=yes DEVICE=eth0 BOOTPROTO=none HWADDR=00:50:56:01:00:01 BROADCAST=192.168.0.255 IPADDR=192.168.0.10 NETMASK=255.255.255.0 NETWORK=192.168.0.0 GATEWAY=192.168.0.1 DNS1=192.168.0.1 DNS2=192.168.0.100 DOMAIN='domain.tld' USERCTL=no IPV6INIT=yes IPV6ADDR=ipv6addr IPV6_AUTOCONF=no IPV6_DEFAULTGW=ipv6addr-gateway IPV6_DEFAULTDEV=eth0 if I would need an additional IPv6 address I'd just add IPV6ADDR_SECONDARIES="ipv6addr" to this file; if I would need an additional IPv4 address this works only by a virtual device e.g. eth0:1 like this: /etc/sysconfig/network-scripts/ifcfg-eth0:1 # Intel Corporation 82545EM Gigabit Ethernet Controller (Copper), Alias 1 TYPE=Ethernet DEVICE=eth0:1 ONPARENT=yes BOOTPROTO=none BROADCAST=192.168.0.255 IPADDR=192.168.0.17 NETMASK=255.255.255.0 NETWORK=192.168.0.0 GATEWAY=192.168.0.1 DNS1=192.168.0.1 DNS2=192.168.0.100 why can't I add this to the virtual device eth0:1, if I needed both an additional IPv4 and an additional IPv6 address? IPV6INIT=yes IPV6ADDR=ipv6addr IPV6_AUTOCONF=no IPV6_DEFAULTGW=ipv6addr-gateway IPV6_DEFAULTDEV=eth0:1 Thanks, Walter