[CentOS] Centos 7 specific cure for Spamassassin DNS lookup problem

Thu Aug 10 08:21:31 UTC 2017
Gary Stainburn <gary at ringways.co.uk>

I have the following error message in my /var/log/spamd

spf: lookup failed: available_nameservers: No DNS servers available!

Having Googled the error message I've found a number of responses which 
involve patching Perl or Spamassassin or other cures. 

Before I start changing things I was wondering if there was a Centos 7 
specific resolution. Where possible, on production machines I prefer to stay 
with RPM's rather than amending software directly.

Also, many of these responses are over 10 years old, so I'm a little sceptical 
about their success today.