Table of Contents

Tinc client

This article relies on the following:

Introduction

Goals

  • Encrypt your internet connection to enforce security and privacy.
    • Prevent traffic leaks and spoofing on the client side.
  • Bypass regional restrictions using commercial providers.
    • Escape client side content filters and internet censorship.
  • Access your LAN services remotely without port forwarding.

Command-line instructions

1. Preparation

Install the required packages. Specify configuration parameters for VPN client. 

# Install packages
opkg update
opkg install tinc
 
# Configuration parameters
VPN_IF="vpn"
VPN_SERV="SERVER_ADDRESS"
VPN_PORT="655"
VPN_ADDR="192.168.9.2/24"
VPN_ADDR6="fd00:9::2/64"

2. Key management

Generate and exchange keys between server and client. 

# Generate keys
mkdir -p /etc/tinc/${VPN_IF}
tinc -n ${VPN_IF} generate-rsa-keys < /dev/null
tinc -n ${VPN_IF} generate-ed25519-keys < /dev/null
VPN_SPUB="$(sed -e "s/^.*\s//" server.pub)"
VPN_CPUB="$(sed -e "s/^.*\s//" /etc/tinc/${VPN_IF}/ed25519_key.pub)"

3. Firewall

Consider VPN network as public. Assign VPN interface to WAN zone to minimize firewall setup. 

# Configure firewall
uci rename firewall.@zone[0]="lan"
uci rename firewall.@zone[1]="wan"
uci del_list firewall.wan.network="${VPN_IF}"
uci add_list firewall.wan.network="${VPN_IF}"
uci commit firewall
service firewall restart

4. VPN service

Configure VPN service. 

# Configure VPN service
uci -q delete tinc.${VPN_IF}
uci set tinc.${VPN_IF}="tinc-net"
uci set tinc.${VPN_IF}.enabled="1"
uci set tinc.${VPN_IF}.Interface="${VPN_IF}"
uci set tinc.${VPN_IF}.Name="client"
uci -q delete tinc.server
uci set tinc.server="tinc-host"
uci set tinc.server.enabled="1"
uci set tinc.server.net="${VPN_IF}"
uci set tinc.server.Name="server"
uci set tinc.server.PublicKey="1"
uci set tinc.server.Ed25519PublicKey="${VPN_SPUB}"
uci set tinc.server.Address="${VPN_SERV}"
uci set tinc.server.Port="${VPN_PORT}"
uci add_list tinc.server.Subnet="0.0.0.0/0"
uci add_list tinc.server.Subnet="::/0"
uci -q delete tinc.client
uci set tinc.client="tinc-host"
uci set tinc.client.enabled="1"
uci set tinc.client.net="${VPN_IF}"
uci set tinc.client.Name="client"
uci set tinc.client.PublicKey="1"
uci set tinc.client.Ed25519PublicKey="${VPN_CPUB}"
uci add_list tinc.client.Subnet="${VPN_ADDR%.*}.2/32"
uci add_list tinc.client.Subnet="${VPN_ADDR6%:*}:2/128"
uci commit tinc
service tinc restart

5. Network

Set up VPN interface. 

# Configure network
uci -q delete network.${VPN_IF}
uci set network.${VPN_IF}="interface"
uci set network.${VPN_IF}.proto="static"
uci set network.${VPN_IF}.ipaddr="${VPN_ADDR}"
uci set network.${VPN_IF}.ip6addr="${VPN_ADDR6}"
uci set network.${VPN_IF}.device="${VPN_IF}"
for IPV in 4 6
do case ${IPV} in
(4) VPN_DST="0.0.0.0/0" ;;
(6) VPN_DST="::/0" ;;
esac
uci set network.lan.ip${IPV}table="1"
uci set network.${VPN_IF}.ip${IPV}table="2"
uci -q delete network.${VPN_IF}_rt${IPV%4}
uci set network.${VPN_IF}_rt${IPV%4}="route${IPV%4}"
uci set network.${VPN_IF}_rt${IPV%4}.interface="${VPN_IF}"
uci set network.${VPN_IF}_rt${IPV%4}.target="${VPN_DST}"
uci -q delete network.lan_${VPN_IF}${IPV%4}
uci set network.lan_${VPN_IF}${IPV%4}="rule${IPV%4}"
uci set network.lan_${VPN_IF}${IPV%4}.in="lan"
uci set network.lan_${VPN_IF}${IPV%4}.lookup="2"
uci set network.lan_${VPN_IF}${IPV%4}.priority="30000"
done
uci commit network
service network restart

Testing

Establish the VPN connection. Verify your routing with traceroute and traceroute6. 

traceroute openwrt.org
traceroute6 openwrt.org

Check your IP and DNS provider.

On router:

  • Go to LuCI > Status > Wireguard and look for peer device connected with an IPv4 or IPv6 address and with a recent handshake time
  • Go to LuCI > Network > Diagnostics and ipv4 ping client device IP eg. 10.0.0.10

On client device depending on wireguard software:

  • Check transfer traffic for tx & rx
  • Ping router internal lan IP
  • Check public IP address in a browser – https://whatsmyip.com – should see public IP address of ISP for the router

Troubleshooting

Collect and analyze the following information. 

# Restart services
service log restart; service tinc restart; sleep 10
 
# Log and status
logread -e tinc; netstat -l -n -p | grep -e tinc
 
# Runtime configuration
pgrep -f -a tinc
ip address show; ip route show table all
ip rule show; ip -6 rule show; nft list ruleset
 
# Persistent configuration
uci show network; uci show firewall; uci show tinc
head -v -n -0 /etc/tinc/*/*/*