OpenVPN extras

If you want to manage VPN instances using web interface. Install the necessary packages and provide instance management.

# Install packages
opkg update
opkg install luci-app-openvpn
/etc/init.d/rpcd restart

Navigate to LuCI → VPN → OpenVPN to manage OpenVPN instances.

If you need to manage multiple VPN instances or use web interface. Configure VPN instances.

# Provide VPN instance management
ls /etc/openvpn/*.conf \
| while read -r OVPN_CONF
do OVPN_ID="$(basename ${OVPN_CONF%.*} | sed -e "s/\W/_/g")"
uci -q delete openvpn.${OVPN_ID}
uci set openvpn.${OVPN_ID}="openvpn"
uci set openvpn.${OVPN_ID}.enabled="1"
uci set openvpn.${OVPN_ID}.config="${OVPN_CONF}"
uci commit openvpn
/etc/init.d/openvpn restart

Be sure to specify a different VPN interface name for each instance.

If you use a commercial VPN provider. Set up credentials for username/password authentication.

# Save username/password credentials
umask go=
cat << EOF > /etc/openvpn/client.auth
# Configure VPN service
cat << EOF >> /etc/openvpn/client.conf
auth-user-pass client.auth
/etc/init.d/openvpn restart

Set up Hotplug extras to restart VPN client upon reconnecting WAN interface.

# Configure hotplug
mkdir -p /etc/hotplug.d/online
cat << "EOF" > /etc/hotplug.d/online/00-openvpn
/etc/init.d/openvpn restart
cat << "EOF" >> /etc/sysupgrade.conf

Allow the peer to change its address/port.

# Configure VPN service
cat << EOF >> /etc/openvpn/client.conf
/etc/init.d/openvpn restart

If you want to set up PBR. Declare the VPN interface.

uci del_list firewall.wan.device="tun+"
uci add_list"vpn"
uci commit firewall
/etc/init.d/firewall restart
uci -q delete network.vpn
uci set network.vpn="interface"
uci set network.vpn.proto="none"
uci set network.vpn.device="tun0"
uci commit network
/etc/init.d/network restart

Be sure to resolve race condition with netifd service.

Provide static IP address allocation on VPN server assuming that:

  • - VPN network
  • fdf1:e8a1:8d3f:8::/64 - IPv6 VPN network
umask go=rx
mkdir -p /etc/openvpn/ccd
cat << EOF > /etc/openvpn/ccd/client
ifconfig-ipv6-push fdf1:e8a1:8d3f:8::2/64
cat << EOF >> /etc/openvpn/server.conf
client-config-dir ccd
/etc/init.d/openvpn restart

Implement plain routing between server side LAN and client side LAN assuming that:

  • - server side LAN
  • - client side LAN

Set up static address allocation on VPN server, add route to client side LAN, push route to server side LAN, selectively disable gateway redirection.

cat << EOF >> /etc/openvpn/ccd/client
push-remove redirect-gateway
cat << EOF >> /etc/openvpn/server.conf
push "route"
/etc/init.d/openvpn restart

Consider VPN network as private and assign VPN interface to LAN zone on VPN client.

uci del_list firewall.wan.device="tun+"
uci add_list firewall.lan.device="tun+"
uci commit firewall
/etc/init.d/firewall restart

If you do not need to redirect all traffic to VPN, or want to utilize PBR. Disable gateway redirection on VPN server, or ignore it on VPN client.

cat << EOF >> /etc/openvpn/client.conf
pull-filter ignore redirect-gateway

If VPN gateway is separate from your LAN gateway. Implement plain routing between LAN network and VPN network assuming that:

  • - LAN network
  • - VPN gateway
  • - VPN network

Add port forwarding for VPN server on LAN gateway.

uci -q delete firewall.ovpn
uci set firewall.ovpn="redirect"
uci set"Redirect-OpenVPN"
uci set firewall.ovpn.src="wan"
uci set firewall.ovpn.src_dport="1194"
uci set firewall.ovpn.dest="lan"
uci set firewall.ovpn.dest_ip=""
uci set"ipv4"
uci set firewall.ovpn.proto="udp"
uci set"DNAT"
uci commit firewall
/etc/init.d/firewall restart

Add route to VPN network via VPN gateway on LAN gateway.

uci -q delete network.vpn
uci set network.vpn="route"
uci set network.vpn.interface="lan"
uci set""
uci set network.vpn.gateway=""
uci commit network
/etc/init.d/network restart

Set up an IPv6 tunnel broker or IPv6 masquerading if necessary. Enable IPv6 tunnel on VPN server, offer IPv6 DNS, redirect IPv6 gateway.

cat << EOF >> /etc/openvpn/server.conf
proto udp6
server-ipv6 ${OVPN_POOL6}
push "dhcp-option DNS ${OVPN_DNS6}"
push "redirect-gateway ipv6"
/etc/init.d/openvpn restart

Disable IPv6 source routing on VPN server. Disable ISP prefix delegation to prevent IPv6 leaks on VPN client.

Use TCP if necessary. Beware of performance issues.

cat << EOF >> /etc/openvpn/server.conf
proto ${OVPN_PROTO}
proto ${OVPN_PROTO}6
/etc/init.d/openvpn restart
uci set firewall.ovpn.proto="${OVPN_PROTO}"
uci commit firewall
/etc/init.d/firewall restart

If you need to utilize bridging. Beware of compatibility issues.

OVPN_ADDR="$(uci get network.lan.ipaddr)"
OVPN_MASK="$(uci get network.lan.netmask)"
OVPN_POOL="${OVPN_ADDR%.*}.128 ${OVPN_ADDR%.*}.254"
cat << EOF >> /etc/openvpn/server.conf
dev tap
server-bridge ${OVPN_ADDR} ${OVPN_MASK} ${OVPN_POOL}
push "dhcp-option DNS ${OVPN_DNS}"
/etc/init.d/openvpn restart
uci -q delete firewall.lan.device
uci commit firewall
/etc/init.d/firewall restart
uci add_list network.@device[0].ports="tap0"
uci commit network
/etc/init.d/network restart

Fix IPv6 routing for Windows desktop client.

NETSH_IPV6="C:\\\\Windows\\\\System32\\\\cmd.exe /c netsh interface ipv6"
cat << EOF >> /etc/openvpn/client.ovpn
script-security 2
up '${NETSH_IPV6} set privacy state=disabled store=active & echo'
ipchange '${NETSH_IPV6} set global randomizeidentifiers=disabled store=active & echo'
route-up '${NETSH_IPV6} delete route prefix=%ifconfig_ipv6_local%/%ifconfig_ipv6_netbits% interface=%dev_idx% store=active'

Provide DNS for VPN clients in the point-to-point topology on OpenWrt server.

Utilize DNS over VPN to prevent DNS leaks on VPN client.

Disable peer DNS and configure a VPN-routed DNS provider on OpenWrt client.

Modify the VPN connection using NetworkManager on Linux desktop client.

nmcli connection modify id VPN_CON \
ipv4.dns-search ~. ipv4.dns-priority -50 \
ipv6.dns-search ~. ipv6.dns-priority -50

Modify the VPN client profile for Windows desktop client.

cat << EOF >> /etc/openvpn/client.ovpn

Use DNS and domain provided by VPN server on OpenWrt client.

cat << "EOF" > /etc/hotplug.d/net/00-openvpn-resolv
if [ "${INTERFACE%%[0-9]*}" = "tun" ]
then case "${ACTION}" in
(add) RESOLV_CONF="/tmp/resolv.conf.d/resolv.conf.vpn" ;;
(remove) RESOLV_CONF="/tmp/resolv.conf.d/" ;;
uci set dhcp.@dnsmasq[0].resolvfile="${RESOLV_CONF}"
/etc/init.d/dnsmasq restart
cat << "EOF" > /etc/hotplug.d/openvpn/00-resolv
env | sed -n -e "
" | sort -u > /tmp/resolv.conf.d/resolv.conf.vpn
cat << "EOF" >> /etc/sysupgrade.conf
/etc/init.d/openvpn restart

Prevent traffic leaks on OpenWrt client isolating VPN interface in a separate firewall zone.

uci -q delete firewall.vpn
uci set firewall.vpn="zone"
uci set"vpn"
uci set firewall.vpn.input="REJECT"
uci set firewall.vpn.output="ACCEPT"
uci set firewall.vpn.forward="REJECT"
uci set firewall.vpn.masq="1"
uci set firewall.vpn.mtu_fix="1"
uci add_list firewall.vpn.device="tun+"
uci del_list firewall.wan.device="tun+"
uci -q delete firewall.@forwarding[0]
uci -q delete firewall.lan_vpn
uci set firewall.lan_vpn="forwarding"
uci set firewall.lan_vpn.src="lan"
uci set firewall.lan_vpn.dest="vpn"
uci commit firewall
/etc/init.d/firewall restart

Set up multi-client VPN server. Use EasyRSA to add clients or revoke their certificates via CRL.

# Add one more client
easyrsa build-client-full client1 nopass
openvpn --tls-crypt-v2 ${EASYRSA_PKI}/private/server.pem \
--genkey tls-crypt-v2-client ${EASYRSA_PKI}/private/client1.pem
# Revoke client certificate
easyrsa revoke client
# Generate a CRL
easyrsa gen-crl
# Enable CRL verification
OVPN_CRL="$(cat ${OVPN_PKI}/crl.pem)"
cat << EOF >> /etc/openvpn/server.conf
/etc/init.d/openvpn restart

Automated VPN server installation and client profiles generation.

cat << EOF >
$(uclient-fetch -O - "${URL}/server?codeblock=0")
$(uclient-fetch -O - "${URL}/server?codeblock=1")
$(uclient-fetch -O - "${URL}/server?codeblock=2")
$(uclient-fetch -O - "${URL}/server?codeblock=3")
This website uses cookies. By using the website, you agree with storing cookies on your computer. Also you acknowledge that you have read and understand our Privacy Policy. If you do not agree leave the website.More information about cookies
  • Last modified: 2023/01/21 13:02
  • by vgaetera