[Samba] resolve errors with Samba 4 dns

[Gary Dale]

I'm running Debian/Jessie on a server which is used as an AD DC. I'm 
getting errors like this:

Hit http://ftp.ca.debian.org jessie InRelease
Hit http://ftp.ca.debian.org jessie/main Sources
Hit http://ftp.ca.debian.org jessie/main amd64 Packages
Hit http://ftp.ca.debian.org jessie/main Translation-en
Err http://ftp3.nrc.ca jessie InRelease
Err http://ftp3.nrc.ca jessie-updates InRelease
Err http://security.debian.org jessie/updates InRelease
Err http://security.debian.org jessie/updates Release.gpg
   Could not resolve 'security.debian.org'
Err http://ftp3.nrc.ca jessie Release.gpg
   Could not resolve 'ftp3.nrc.ca'
Err http://ftp3.nrc.ca jessie-updates Release.gpg
   Could not resolve 'ftp3.nrc.ca'
W: Failed to fetch http://ftp3.nrc.ca/debian/dists/jessie/InRelease:
W: Failed to fetch 
http://security.debian.org/dists/jessie/updates/InRelease:
W: Failed to fetch 
http://ftp3.nrc.ca/debian/dists/jessie-updates/InRelease:
W: Failed to fetch http://ftp3.nrc.ca/debian/dists/jessie/Release.gpg: 
Could not resolve 'ftp3.nrc.ca'
W: Failed to fetch 
http://ftp3.nrc.ca/debian/dists/jessie-updates/Release.gpg: Could not 
resolve 'ftp3.nrc.ca'
W: Failed to fetch 
http://security.debian.org/dists/jessie/updates/Release.gpg: Could not 
resolve 'security.debian.org'
W: Some index files failed to download. They have been ignored, or old 
ones used instead.

since installing Samba 4 and using its DNS server. I've tried forwarding 
to both my router, which has dns, and directly to Google's 8.8.8.8 DNS 
servers but the problems persist.

On workstations, e-mail sometimes gets through and sometimes fails. 
Other Internet services are similarly iffy.

Any suggestions?