diff --git a/tools/naptr-eduroam.sh b/tools/naptr-eduroam.sh
index 1d45c4d..e5d2da8 100755
--- a/tools/naptr-eduroam.sh
+++ b/tools/naptr-eduroam.sh
@@ -14,7 +14,6 @@ usage() {
 
 test -n "${1}" || usage
 
-REALM="${1}"
 DIGCMD=$(command -v dig)
 HOSTCMD=$(command -v host)
 PRINTCMD=$(command -v printf)
@@ -69,6 +68,12 @@ host_it_naptr() {
     done
 }
 
+REALM=$(validate_host ${1})
+if [ -z "${REALM}" ]; then
+    echo "Error: realm \"${1}\" failed validation"
+    usage
+fi
+
 if [ -x "${DIGCMD}" ]; then
     SERVERS=$(dig_it_naptr)
 elif [ -x "${HOSTCMD}" ]; then
diff --git a/tools/radsec-dynsrv.sh b/tools/radsec-dynsrv.sh
index 9ea182c..a1bbed3 100755
--- a/tools/radsec-dynsrv.sh
+++ b/tools/radsec-dynsrv.sh
@@ -14,7 +14,6 @@ usage() {
 
 test -n "${1}" || usage
 
-REALM="${1}"
 DIGCMD=$(command -v digaaa)
 HOSTCMD=$(command -v host)
 PRINTCMD=$(command -v printf)
@@ -47,6 +46,12 @@ host_it() {
    done
 }
 
+REALM=$(validate_host ${1})
+if test -z "${REALM}" ; then
+    echo "Error: realm \"${1}\" failed validation"
+    usage
+fi
+
 if test -x "${DIGCMD}" ; then
    SERVERS=$(dig_it)
 elif test -x "${HOSTCMD}" ; then