diff --git a/functions b/functions
index 8cb703c567..5fae560f57 100644
--- a/functions
+++ b/functions
@@ -123,6 +123,37 @@ function get_field() {
 }
 
 
+# Get the default value for HOST_IP
+# get_default_host_ip fixed_range floating_range host_ip_iface host_ip
+function get_default_host_ip() {
+    local fixed_range=$1
+    local floating_range=$2
+    local host_ip_iface=$3
+    local host_ip=$4
+
+    # Find the interface used for the default route
+    host_ip_iface=${host_ip_iface:-$(ip route | sed -n '/^default/{ s/.*dev \(\w\+\)\s\+.*/\1/; p; }' | head -1)}
+    # Search for an IP unless an explicit is set by ``HOST_IP`` environment variable
+    if [ -z "$host_ip" -o "$host_ip" == "dhcp" ]; then
+        host_ip=""
+        host_ips=`LC_ALL=C ip -f inet addr show ${host_ip_iface} | awk '/inet/ {split($2,parts,"/");  print parts[1]}'`
+        for IP in $host_ips; do
+            # Attempt to filter out IP addresses that are part of the fixed and
+            # floating range. Note that this method only works if the ``netaddr``
+            # python library is installed. If it is not installed, an error
+            # will be printed and the first IP from the interface will be used.
+            # If that is not correct set ``HOST_IP`` in ``localrc`` to the correct
+            # address.
+            if ! (address_in_net $IP $fixed_range || address_in_net $IP $floating_range); then
+                host_ip=$IP
+                break;
+            fi
+        done
+    fi
+    echo $host_ip
+}
+
+
 function _get_package_dir() {
     local pkg_dir
     if is_ubuntu; then
diff --git a/stack.sh b/stack.sh
index 0f5401a771..0fae33fbf6 100755
--- a/stack.sh
+++ b/stack.sh
@@ -223,27 +223,9 @@ FIXED_RANGE=${FIXED_RANGE:-10.0.0.0/24}
 FIXED_NETWORK_SIZE=${FIXED_NETWORK_SIZE:-256}
 NETWORK_GATEWAY=${NETWORK_GATEWAY:-10.0.0.1}
 
-# Find the interface used for the default route
-HOST_IP_IFACE=${HOST_IP_IFACE:-$(ip route | sed -n '/^default/{ s/.*dev \(\w\+\)\s\+.*/\1/; p; }' | head -1)}
-# Search for an IP unless an explicit is set by ``HOST_IP`` environment variable
-if [ -z "$HOST_IP" -o "$HOST_IP" == "dhcp" ]; then
-    HOST_IP=""
-    HOST_IPS=`LC_ALL=C ip -f inet addr show ${HOST_IP_IFACE} | awk '/inet/ {split($2,parts,"/");  print parts[1]}'`
-    for IP in $HOST_IPS; do
-        # Attempt to filter out IP addresses that are part of the fixed and
-        # floating range. Note that this method only works if the ``netaddr``
-        # python library is installed. If it is not installed, an error
-        # will be printed and the first IP from the interface will be used.
-        # If that is not correct set ``HOST_IP`` in ``localrc`` to the correct
-        # address.
-        if ! (address_in_net $IP $FIXED_RANGE || address_in_net $IP $FLOATING_RANGE); then
-            HOST_IP=$IP
-            break;
-        fi
-    done
-    if [ "$HOST_IP" == "" ]; then
-        die $LINENO "Could not determine host ip address. Either localrc specified dhcp on ${HOST_IP_IFACE} or defaulted"
-    fi
+HOST_IP=$(get_default_host_ip $FIXED_RANGE $FLOATING_RANGE "$HOST_IP_IFACE" "$HOST_IP")
+if [ "$HOST_IP" == "" ]; then
+    die $LINENO "Could not determine host ip address. Either localrc specified dhcp on ${HOST_IP_IFACE} or defaulted"
 fi
 
 # Allow the use of an alternate hostname (such as localhost/127.0.0.1) for service endpoints.