diff --git a/getssl b/getssl
index 594861d..91e3c36 100755
--- a/getssl
+++ b/getssl
@@ -47,13 +47,15 @@
 # 2016-04-15 Remove NS Lookup of A record when using dns validation (0.29) - pecigonzalo
 # 2016-04-17 Improving the wording in a couple of comments and info statements. (0.30)
 # 2016-05-04 Improve check for if DNS_DEL_COMMAND is blank. (0.31)
-# 2016-05-06 Setting umask to 077 for security of private keys etc. (0.32) 
-# 2016-05-10 update to reflect changes in staging ACME server json (0.33)
-# 2016-05-10 tidying up checking of json following AMCE changes. (0.34)
+# 2016-05-06 Setting umask to 077 for security of private keys etc. (0.32)
+# 2016-05-20 update to reflect changes in staging ACME server json (0.33)
+# 2016-05-20 tidying up checking of json following AMCE changes. (0.34)
+# 2016-05-21 added AUTH_DNS_SERVER to getssl.cfg as optional definition of authoritative DNS server (0.35)
 # ---------------------------------------------------------------------------
 
+
 PROGNAME=${0##*/}
-VERSION="0.34"
+VERSION="0.35"
 
 # defaults
 CA="https://acme-staging.api.letsencrypt.org"
@@ -856,10 +858,14 @@ for d in $alldomains; do
     debug "adding dns via command: $DNS_ADD_COMMAND $d $auth_key"
     $DNS_ADD_COMMAND "$d" "$auth_key"
 
-    # find a primary / authoratative DNS server for the domain
-    primary_ns=$(nslookup -type=soa "${d}" | grep origin | awk '{print $3}')
-    if [ -z "$primary_ns" ]; then
-      primary_ns=$(nslookup -type=soa "${d}" -debug=1 | grep origin | awk '{print $3}')
+    # find a primary / authoritative DNS server for the domain
+    if [ -z "$AUTH_DNS_SERVER" ]; then
+      primary_ns=$(nslookup -type=soa "${d}" | grep origin | awk '{print $3}')
+      if [ -z "$primary_ns" ]; then
+        primary_ns=$(nslookup -type=soa "${d}" -debug=1 | grep origin | awk '{print $3}')
+      fi
+    else
+      primary_ns="$AUTH_DNS_SERVER"
     fi
     debug primary_ns "$primary_ns"