Okay, dns has corrected and I can use my webbrowser to see our existing website on firstdomain.com.
System mail is sent to my user-at-firstdomain.com and when I used tools-squirrelmail to access my email I found
WARNING: service dns not running (server: server,firstdomain.com, port: 53)!
These notices have been posting every half-hour since 10:00am local time this morning.
Checking services shows that BIND is "OFFLINE"