I am able to bring up a bonded NIC in Centos4 without requiring to bring up the bond0 with an ip address, but with CentOS-3 I must assign the NIC an address or eth0 and eth1 will not slave. I need to bring bond0 up without an ip address becuase I will be using tagged VLANs. ie. <snip /etc/sysconfig/network-scripts/ifcfg-bond0> DEVICE=bond0 BOOTPROTO=none ONBOOT=yes IPADDR=169.254.0.1 USERCTL=no </snip> I can later manually do something like the following from a post network script, but I am wondering why this is different in CentOS-4. ifconfig bond0 0.0.0.0 ifconfig eth0 0.0.0.0 ifconfig eth1 0.0.0.0 if I change the ifcfg-bond0 to not have an ip address. ie. <snip /etc/sysconfig/network-scripts/ifcfg-bond0> DEVICE=bond0 BOOTPROTO=none ONBOOT=yes #IPADDR=169.254.0.1 USERCTL=no </snip> Then when I restart the network neither eth0 or eth1 are enslaved.