Configuring Automatic Location Switching (ALS) for Symantec Endpoint Protection (SEP) for Mac clients with a type of 'DNS Lookup' and option of 'If the client computer cannot resolve the host name specified below' will result in client unable to switch location when it can successfully resolve the defined host name/IP address.
Logic for this particular location type appears to have reverse logic on the SEP for Mac clients. 'If the client computer cannot resolve the host name specified below' will return true when the client is able to resolve the specified host name. Whereas 'If the client computer can resolve the host name specified below' will return false in that same scenario. This is opposite of how the help file explains it and how the Windows SEP client works.