2. So there is a conflict

What are your options when there are such conflicts? When more than one host is sharing one IP number, one is known as the official host and the reverse mapping points to it. Therefore, you mostly have this DNS relation:

        host.domain -> IP number
        IP number   -> host.domain
        

All other host names sharing the IP will only have the first line of this relation. Linuxconf enforces this. So when there is a conflict your options are:

• Cancel the dialog and pick another IP number
• Tell linuxconf that this host is the "main" one so linuxconf will use this host name to do the reverse mapping (and will delete any previous reverse mapping on this IP number).
• Tell linuxconf that this host is not the "main" one. Linuxconf won't update the reverse mapping.