IP alias permanently assigned in AIX

Technote (troubleshooting)

 

Problem(Abstract)

 Upon reboot an IP alias is automatically assigned to an interface by the operating system. How do I prevent this ?

 Symptom

 

Prior to the start of the cluster or at least the start of IBM.GblResRM, an IP Alias is already being assigned to a NIC.

 

Cause

 In AIX you can set a permanent IP Alias to an interface so that it will be automatically re-assigned after a reboot. The command that does this is "chdev".

For example, to assign an alias :

chdev -l en0 -a alias4=192.168.0.100,255.255.255.0

 Resolving the problem

 To remove the alias, issue the following command:

chdev -l enX delalias4=<IP_Address_of_Alias>,<Subnet_mask>

where:

X=number of the network interface the alias is assigned to, example, en0, en1, en2...
IP_Address_of_Alias= The alias IP Address, not the default NIC/System address for that adapter
Subnet_Mask= The subnet mask used to create the alias.

The values for the above parameters can be obtained from the output of "ifconfig -a".