Modify realm domains
DNS check: When manually adding a domain to the list, a DNS check is performed by default. It ensures that the domain is associated with the IPA realm, by checking whether the domain has a _kerberos TXT record containing the IPA realm name. This check can be skipped by specifying –force option.
Removal: when a realm domain which has a matching DNS zone managed by IPA is being removed, a corresponding _kerberos TXT record in the zone is removed automatically as well. Other records in the zone or the zone itself are not affected.