Local Domain refers to the most detailed domain your computer resides in.
Determine your Local Domain this is, by looking at the domain name reserved for your computer: the domain name of the most detailed domain is the domain name of your computer with the first word omitted. For example, "yourlocaldomain.com".
The local domain is often the IP number range and/or domain of your organisation or ISP.
If your company domain names are "mycompany.com" and "myothercompany.com", you would specify: mycompany.com