this is obsolete doc -- see http://doc.nethence.com/ instead

Redhat Networking 

Settting up NetworkManager 

If you prefer to keep NetworkManager up and running, either use the TUI, 

  nmtui 

or manually, 

vi /etc/hostname 

cd /etc/sysconfig/network-scripts/ 

cp ifcfg-eno16780032 DIST.ifcfg-eno16780032 

vi ifcfg-eno16780032 

BOOTPROTO=static 

DNS1=10.0.0.X 

DNS2=10.0.0.X 

DNS3=10.0.0.X 

DOMAIN=example.local 

IPADDR=10.0.0.X 

PREFIX=22 

GATEWAY=10.0.0.X 

Static routes 

the device dependent way 

ifconfig 

on RHEL6, 

vi /etc/sysconfig/network-scripts/route-eth0 

on RHEL7 VM, 

vi /etc/sysconfig/network-scripts/route-ens192 

network.0.0/16 via local_network_ip_address 

#network.0.0/16 via local_network_ip_address via eth0 

#network.0.0/16 via local_network_ip_address via ens192 

the right way 

cd /etc/sysconfig/ 

vi static-routes 

any net network.0.0 netmask 255.255.0.0 gw local_network_ip_address 

apply 

(also works if using NetworkManager), 

on RHEL6, 

  service network restart 

on RHEL7, 

  systemctl restart network 

Setting up VLAN tagging 

If you really want to use VLAN tagging on the OS level (eeeeeeeeeeek), 

netif=eth1 

tag=9 

cd /etc/sysconfig/network-scripts/ 

cat > ifcfg-$netif <<EOF 

DEVICE=$netif 

TYPE=Ethernet 

BOOTPROTO=none 

ONBOOT=yes 

EOF 

cat > ifcfg-$netif.$tag <<EOF 

DEVICE=$netif.$tag 

BOOTPROTO=none 

ONBOOT=yes 

IPADDR=10.9.9.1 

NETMASK=255.255.255.0 

VLAN=yes 

EOF 

unset netif tag 

service network restart 

Refs. 

7.4. CONFIGURE 802.1Q VLAN TAGGING USING THE COMMAND LINE: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Networking_Guide/sec-Configure_802_1Q_VLAN_Tagging_Using_the_Command_Line.html 

Enabling VLAN tagging on Redhat Linux: http://technodrone.blogspot.com/2011/10/enabling-vlan-tagging-on-redhat-linux.html