diff --git a/smf/ip_utils.py b/smf/ip_utils.py
index a1e9977..576535d 100755
--- a/smf/ip_utils.py
+++ b/smf/ip_utils.py
@@ -60,8 +60,7 @@ def start(ip_range):
         raise ValueError('Invalid UE IPv4 range. Only one IP given')
     else:
         first_ip_addr = first_ip_addr.exploded
-        ip_netmask_prefix = ip_range.prefixlen
-        print(str(first_ip_addr) + '/' + str(ip_netmask_prefix))
+        print(str(first_ip_addr))
 
 if __name__ == '__main__':
     try:
diff --git a/smf/smf.yaml b/smf/smf.yaml
index 9e44335..5ac76a7 100644
--- a/smf/smf.yaml
+++ b/smf/smf.yaml
@@ -38,16 +38,20 @@ smf:
         upf:
           - address: UPF_IP
     session:
-      - subnet: UE_IPV4_INTERNET_TUN_IP
+      - subnet: UE_IPV4_INTERNET_SUBNET
+        gateway: UE_IPV4_INTERNET_TUN_IP
         dnn: internet
         dev: ogstun
-      - subnet: 2001:230:cafe::1/48
+      - subnet: 2001:230:cafe::/48
+        gateway: 2001:230:cafe::1
         dnn: internet
         dev: ogstun
-      - subnet: UE_IPV4_IMS_TUN_IP
+      - subnet: UE_IPV4_IMS_SUBNET
+        gateway: UE_IPV4_IMS_TUN_IP
         dnn: ims
         dev: ogstun2
-      - subnet: 2001:230:babe::1/48
+      - subnet: 2001:230:babe::/48
+        gateway: 2001:230:babe::1
         dnn: ims
         dev: ogstun2
     dns:
diff --git a/smf/smf_4g.yaml b/smf/smf_4g.yaml
index f489beb..8d5f6e9 100644
--- a/smf/smf_4g.yaml
+++ b/smf/smf_4g.yaml
@@ -29,16 +29,20 @@ smf:
         upf:
           - address: UPF_IP
     session:
-      - subnet: UE_IPV4_INTERNET_TUN_IP
+      - subnet: UE_IPV4_INTERNET_SUBNET
+        gateway: UE_IPV4_INTERNET_TUN_IP
         dnn: internet
         dev: ogstun
-      - subnet: 2001:230:cafe::1/48
+      - subnet: 2001:230:cafe::/48
+        gateway: 2001:230:cafe::1
         dnn: internet
         dev: ogstun
-      - subnet: UE_IPV4_IMS_TUN_IP
+      - subnet: UE_IPV4_IMS_SUBNET
+        gateway: UE_IPV4_IMS_TUN_IP
         dnn: ims
         dev: ogstun2
-      - subnet: 2001:230:babe::1/48
+      - subnet: 2001:230:babe::/48
+        gateway: 2001:230:babe::1
         dnn: ims
         dev: ogstun2
     dns:
diff --git a/smf/smf_init.sh b/smf/smf_init.sh
index 67ae9bc..1d49728 100755
--- a/smf/smf_init.sh
+++ b/smf/smf_init.sh
@@ -51,7 +51,9 @@ sed -i 's|UPF_IP|'$UPF_IP'|g' install/etc/open5gs/smf.yaml
 sed -i 's|SMF_DNS1|'$SMF_DNS1'|g' install/etc/open5gs/smf.yaml
 sed -i 's|SMF_DNS2|'$SMF_DNS2'|g' install/etc/open5gs/smf.yaml
 sed -i 's|UE_IPV4_INTERNET_TUN_IP|'$UE_IPV4_INTERNET_TUN_IP'|g' install/etc/open5gs/smf.yaml
+sed -i 's|UE_IPV4_INTERNET_SUBNET|'$UE_IPV4_INTERNET'|g' install/etc/open5gs/smf.yaml
 sed -i 's|UE_IPV4_IMS_TUN_IP|'$UE_IPV4_IMS_TUN_IP'|g' install/etc/open5gs/smf.yaml
+sed -i 's|UE_IPV4_IMS_SUBNET|'$UE_IPV4_IMS'|g' install/etc/open5gs/smf.yaml
 sed -i 's|PCSCF_IP|'$PCSCF_IP'|g' install/etc/open5gs/smf.yaml
 sed -i 's|MAX_NUM_UE|'$MAX_NUM_UE'|g' install/etc/open5gs/smf.yaml
 sed -i 's|SMF_IP|'$SMF_IP'|g' install/etc/freeDiameter/smf.conf
diff --git a/upf/ip_utils.py b/upf/ip_utils.py
index a1e9977..576535d 100755
--- a/upf/ip_utils.py
+++ b/upf/ip_utils.py
@@ -60,8 +60,7 @@ def start(ip_range):
         raise ValueError('Invalid UE IPv4 range. Only one IP given')
     else:
         first_ip_addr = first_ip_addr.exploded
-        ip_netmask_prefix = ip_range.prefixlen
-        print(str(first_ip_addr) + '/' + str(ip_netmask_prefix))
+        print(str(first_ip_addr))
 
 if __name__ == '__main__':
     try:
diff --git a/upf/upf.yaml b/upf/upf.yaml
index bae3ede..ed811e3 100644
--- a/upf/upf.yaml
+++ b/upf/upf.yaml
@@ -18,16 +18,20 @@ upf:
         - address: UPF_IP
           advertise: UPF_ADVERTISE_IP
     session:
-      - subnet: UE_IPV4_INTERNET_TUN_IP
-        dev: ogstun
+      - subnet: UE_IPV4_INTERNET_SUBNET
+        gateway: UE_IPV4_INTERNET_TUN_IP
         dnn: internet
-      - subnet: 2001:230:cafe::1/48
         dev: ogstun
+      - subnet: 2001:230:cafe::/48
+        gateway: 2001:230:cafe::1
         dnn: internet
-      - subnet: UE_IPV4_IMS_TUN_IP
+        dev: ogstun
+      - subnet: UE_IPV4_IMS_SUBNET
+        gateway: UE_IPV4_IMS_TUN_IP
         dnn: ims
         dev: ogstun2
-      - subnet: 2001:230:babe::1/48
+      - subnet: 2001:230:babe::/48
+        gateway: 2001:230:babe::1
         dnn: ims
         dev: ogstun2
     metrics:
diff --git a/upf/upf_init.sh b/upf/upf_init.sh
index d72ef61..042df63 100755
--- a/upf/upf_init.sh
+++ b/upf/upf_init.sh
@@ -41,7 +41,9 @@ cp /mnt/upf/upf.yaml install/etc/open5gs
 sed -i 's|UPF_IP|'$UPF_IP'|g' install/etc/open5gs/upf.yaml
 sed -i 's|SMF_IP|'$SMF_IP'|g' install/etc/open5gs/upf.yaml
 sed -i 's|UE_IPV4_INTERNET_TUN_IP|'$UE_IPV4_INTERNET_TUN_IP'|g' install/etc/open5gs/upf.yaml
+sed -i 's|UE_IPV4_INTERNET_SUBNET|'$UE_IPV4_INTERNET'|g' install/etc/open5gs/upf.yaml
 sed -i 's|UE_IPV4_IMS_TUN_IP|'$UE_IPV4_IMS_TUN_IP'|g' install/etc/open5gs/upf.yaml
+sed -i 's|UE_IPV4_IMS_SUBNET|'$UE_IPV4_IMS'|g' install/etc/open5gs/upf.yaml
 sed -i 's|UPF_ADVERTISE_IP|'$UPF_ADVERTISE_IP'|g' install/etc/open5gs/upf.yaml
 sed -i 's|MAX_NUM_UE|'$MAX_NUM_UE'|g' install/etc/open5gs/upf.yaml