diff --git a/Dockerfiles.d/Dockerfile.vnet_router0a b/Dockerfiles.d/Dockerfile.vnet_router0a
index 74f8ee75b0abb05a3f98e0c97c7734eeb5fcf562..343fff01eb060d56740d44424e73016e56622466 100644
--- a/Dockerfiles.d/Dockerfile.vnet_router0a
+++ b/Dockerfiles.d/Dockerfile.vnet_router0a
@@ -32,9 +32,9 @@ FROM ubuntu:18.04
 
 # 2. install all dependencies in advance 
 RUN apt-get -qqy update
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp
   
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
 
 # 3. copy yang config
 RUN mkdir -p /opt/dev
diff --git a/Dockerfiles.d/Dockerfile.vnet_router1 b/Dockerfiles.d/Dockerfile.vnet_router1
index 3d112b56087d76ea10112cbbc8b9cbf8ecd1bcd6..32dac9fa9764f69fb2efc7f2035b8f29eeba5b30 100644
--- a/Dockerfiles.d/Dockerfile.vnet_router1
+++ b/Dockerfiles.d/Dockerfile.vnet_router1
@@ -59,7 +59,7 @@ FROM cejkat/fod-router
 
 # 2. install all dependencies in advance (/fod_vnet_router --init.sysstart will check again and might install anything still missing)
 RUN apt-get -qqy update
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp
 
 # 3. copy vnet_router management script + snmp feeder pass_persisttest_bgpflowspec (+ pass_persisttest only for testing/demonstration)
 COPY vnet_router/fod_vnet_router /
diff --git a/Dockerfiles.d/Dockerfile.vnet_router2.debian b/Dockerfiles.d/Dockerfile.vnet_router2.debian
index 3e084577fa3f84f13692f9b87f3f2fb6131295de..b1d0ce60d20f23266f1d38fbfed3fcc53122328c 100644
--- a/Dockerfiles.d/Dockerfile.vnet_router2.debian
+++ b/Dockerfiles.d/Dockerfile.vnet_router2.debian
@@ -61,9 +61,9 @@ FROM debian:buster
 
 # 2. install all dependencies in advance (/fod_vnet_router --init.sysstart will check again and might install anything still missing)
 RUN apt-get -qqy update
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp vim less
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp vim less
   
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
 
 # 3. copy vnet_router management script + snmp feeder pass_persisttest_bgpflowspec (+ pass_persisttest only for testing/demonstration)
 # 3. copy yang config
diff --git a/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp b/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp
index cfc1189013a3c6d922328a892f9d59fad163591a..d051f0216e76eb157eb48ba4d74d1a634db321f8 100644
--- a/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp
+++ b/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp
@@ -61,12 +61,12 @@ FROM debian:bullseye
 
 # 2. install all dependencies in advance (/fod_vnet_router --init.sysstart will check again and might install anything still missing)
 RUN apt-get -qqy update
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp vim less
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp vim less
   
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
 
 #RUN apt-get -qqy install exabgp quagga bird
-RUN apt-get -qqy install exabgp bird2
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install exabgp bird2
 
 # 3. copy vnet_router management script + snmp feeder pass_persisttest_bgpflowspec (+ pass_persisttest only for testing/demonstration)
 # 3. copy yang config
diff --git a/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp1 b/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp1
index 926182a735df1d1dc794f5c413a24308a1e84ddf..a587fcb4519a9e0edcb5c19c2d076b0980bc4e13 100644
--- a/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp1
+++ b/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp1
@@ -61,11 +61,11 @@ FROM debian:buster
 
 # 2. install all dependencies in advance (/fod_vnet_router --init.sysstart will check again and might install anything still missing)
 RUN apt-get -qqy update
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp vim less
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp vim less
   
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
 
-RUN apt-get -qqy install exabgp quagga bird
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install exabgp quagga bird
 
 # 3. copy vnet_router management script + snmp feeder pass_persisttest_bgpflowspec (+ pass_persisttest only for testing/demonstration)
 # 3. copy yang config
diff --git a/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp2 b/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp2
index 1e3e30157982acd7cd9f69ce0b04b13276120eae..b5ebd5b8e91789c7b652f28e169e609ec6600f3e 100644
--- a/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp2
+++ b/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp2
@@ -61,12 +61,12 @@ FROM debian:bullseye
 
 # 2. install all dependencies in advance (/fod_vnet_router --init.sysstart will check again and might install anything still missing)
 RUN apt-get -qqy update
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp vim less
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp vim less
   
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
 
 #RUN apt-get -qqy install exabgp quagga bird
-RUN apt-get -qqy install exabgp bird2
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install exabgp bird2
 
 # 3. copy vnet_router management script + snmp feeder pass_persisttest_bgpflowspec (+ pass_persisttest only for testing/demonstration)
 # 3. copy yang config
diff --git a/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp2.topo2 b/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp2.topo2
index 2ae4d3af0d44507a7464979a121af818c18fa3cd..6c95780c159bfcba8579bb45d613d888adb05ddf 100644
--- a/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp2.topo2
+++ b/Dockerfiles.d/Dockerfile.vnet_router2.debian.exabgp2.topo2
@@ -63,12 +63,12 @@ FROM debian:bullseye
 
 # 2. install all dependencies in advance (/fod_vnet_router --init.sysstart will check again and might install anything still missing)
 RUN apt-get -qqy update
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp vim less
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp vim less
   
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
 
 #RUN apt-get -qqy install exabgp quagga bird
-RUN apt-get -qqy install exabgp bird2
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install exabgp bird2
 
 # 3. copy vnet_router management script + snmp feeder pass_persisttest_bgpflowspec (+ pass_persisttest only for testing/demonstration)
 # 3. copy yang config
diff --git a/Dockerfiles.d/Dockerfile.vnet_router2.old b/Dockerfiles.d/Dockerfile.vnet_router2.old
index d1fac82d9f6592c5533d363b3df4a3c8ad2f9af0..bffa163033def633604ac18c4f01d5cf4be14a05 100644
--- a/Dockerfiles.d/Dockerfile.vnet_router2.old
+++ b/Dockerfiles.d/Dockerfile.vnet_router2.old
@@ -59,9 +59,9 @@ FROM cejkat/fod-router
 
 # 2. install all dependencies in advance (/fod_vnet_router --init.sysstart will check again and might install anything still missing)
 RUN apt-get -qqy update
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp
   
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
 
 # 3. copy vnet_router management script + snmp feeder pass_persisttest_bgpflowspec (+ pass_persisttest only for testing/demonstration)
 COPY vnet_router/configuration.yang /opt/dev/
diff --git a/Dockerfiles.d/Dockerfile.vnet_router2.ubuntu b/Dockerfiles.d/Dockerfile.vnet_router2.ubuntu
index e5cbb3e1b32a6b4431863f878a309d58dc7207ec..41b1b1f0ec6da3b94139c9da9d3ade93556e55cc 100644
--- a/Dockerfiles.d/Dockerfile.vnet_router2.ubuntu
+++ b/Dockerfiles.d/Dockerfile.vnet_router2.ubuntu
@@ -60,9 +60,9 @@ FROM ubuntu:18.04
 
 # 2. install all dependencies in advance (/fod_vnet_router --init.sysstart will check again and might install anything still missing)
 RUN apt-get -qqy update
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp vim less
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install mininet iptables iproute2 tcpdump tshark iputils-ping iputils-tracepath hping3 gawk sshpass lsof strace snmpd snmp vim less
   
-RUN DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
+RUN apt-get -qqy update && DEBIAN_FRONTEND="noninteractive" apt-get -qqy install netconfd yangcli socat openssh-server rsyslog
 
 # 3. copy vnet_router management script + snmp feeder pass_persisttest_bgpflowspec (+ pass_persisttest only for testing/demonstration)
 # 3. copy yang config