As shown in the diagram we installed and configured OpenVPN on the CentOS Server which already has Squid Web Proxy (for internet access) along with the DHCP service. We created a couple of virtual machines for a lab setup with their ip addresses in the 192.168.3.0/24 subnet.The customer wanted to connect to the LAB through VPN, so OpenVPN was installed on the CentOS Server with the below configuration. Also VPN port 1337 was forwarded on the ADSL modem. While testing we were able to successfully establish connection with the OpenVPN server and get an ip from it. But we are unable to even ping the lab machines.Packet forwarding was already enabled for Squid. Please help us out.
Tutorial Link we followed
https://www.howtoforge.com/tutorial/how-to-install-openvpn-on-centos-7/
[root@mail2 openvpn]# iptables -t nat -A POSTROUTING -s 192.168.200.024 -o eth0 -j MASQUERADE
[root@mail2 openvpn]# vim /etc/openvpn/server.conf
#ca certificate
ca /etc/openvpn/keys/ca.crt
#Server Certificate
cert /etc/openvpn/keys/server.crt
#Server Key and keep this is secret
key /etc/openvpn/keys/server.key
#See the size a dh key in /etc/openvpn/keys/
dh /etc/openvpn/keys/dh2048.pem
#Internal IP will get when already connect
server 192.168.200.0 255.255.255.0
#this line will redirect all traffic through our OpenVPN
push "redirect-gateway def1 bypass-dhcp"
#Provide DNS servers to the client, you can use goolge DNS
push "dhcp-option DNS 8.8.8.8"
push "dhcp-option DNS 8.8.4.4"
#Enable multiple client to connect with same key
duplicate-cn
keepalive 20 60
comp-lzo
persist-key
persist-tun
daemon
#enable log
log-append /var/log/myvpn/openvpn.log
#Log Level
verb 3
