Users who were using DNS names to connect to resources in the sysplex will be affected by converting to a sysplex subplexing environment. Some DNS names that existed before the migration will no longer exist, and users will need to use new DNS names to connect to the subplex resources.
For example, users that used the name ftp.mvsplex.mycorp.com might now need to use the domain name of the subplex that they are now required to use, such as ftp.mvsplex0212.mycorp.com. You can make some of this transition more transparent to the users by adding the new domain names to the resolver configuration files that are in use throughout your network. Consider adding the new domain names to the resolver configuration SEARCH directive.