Ubuntu - VPN - OpenVPN - Server configuration file (/etc/openvpn/server.conf)

/etc/openvpn/server.conf

port 1194
proto tcp
dev tun
ca ca.crt
cert server.crt
key server.key
dh dh.pem
user nobody
group nogroup
topology subnet
server 192.168.2.0 255.255.255.0
ifconfig-pool-persist ipp.txt
cipher AES-256-CBC
auth SHA512
tls-version-min 1.2
tls-cipher TLS-DHE-RSA-WITH-AES-256-GCM-SHA384
push "dhcp-option DNS 192.168.1.1"
push "dhcp-option DOMAIN local.domain"
push "route 192.168.0.0 255.255.0.0"
keepalive 10 120
persist-key
persist-tun
crl-verify crl.pem
tls-server
tls-auth tls-auth.key 0
log /var/log/openvpn/openvpn.log
status /var/log/openvpn/status.log 20

NOTE: Ensure that ther OpenVPN IP pool (the server 192.168.2.0 255.255.255.0 line) does not conflict with the current LAN.

All local resources are at 192.168.1.XXX.
All OpenVPN clients are at 192.168.2.XXX.
push dhcp-option DNS 192.168.1.1 tells the server to send the address of the local networks DNS server to the client.
push dhcp-option DOMAIN local.domain tells the server to send the local domain to the client as a place for it to search for hostnames that are used by not fully qualified.