PPPoSSH client

This article relies on the following:

Accessing web interface / command-line interface
Managing configs / packages / services / logs

This how-to describes the method for setting up PPPoSSH client on OpenWrt.
Follow PPPoSSH server for server setup and PPPoSSH extras for additional tuning.

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.

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

# Install packages
opkg update
opkg install pppossh
 
# Configuration parameters
VPN_IF="vpn"
VPN_PORT="22"
VPN_SERV="SERVER_ADDRESS"
VPN_ADDR="192.168.9.2 192.168.9.1"
VPN_USER="root"

Generate and exchange keys between server and client. Set up key-based authentication.

# Client private key
VPN_KEY="/etc/dropbear/dropbear_ed25519_host_key"
 
# Generate client public key
dropbearkey -y -f ${VPN_KEY} \
| sed -n -e "/^ssh-\S*\s/p" > sshclient.pub
 
# Server public key
VPN_PUB="$(cat sshserver.pub)"
 
# Configure PKI
mkdir -p /root/.ssh
cat << EOF >> /root/.ssh/known_hosts
${VPN_SERV} ${VPN_PUB% *}
EOF
cat << EOF >> /etc/sysupgrade.conf
/root/.ssh
EOF

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

Set up VPN interface.

# Configure network
uci -q delete network.${VPN_IF}
uci set network.${VPN_IF}="interface"
uci set network.${VPN_IF}.proto="pppossh"
uci set network.${VPN_IF}.server="${VPN_SERV}"
uci set network.${VPN_IF}.port="${VPN_PORT}"
uci set network.${VPN_IF}.ipaddr="${VPN_ADDR% *}"
uci set network.${VPN_IF}.peeraddr="${VPN_ADDR#* }"
uci set network.${VPN_IF}.sshuser="${VPN_USER}"
uci add_list network.${VPN_IF}.identity="${VPN_KEY}"
uci set network.${VPN_IF}.ipv6="1"
uci commit network
service network restart

Configure dynamic connection if necessary.

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

traceroute openwrt.org
traceroute6 openwrt.org

Check your IP and DNS provider.

Collect and analyze the following information.

# Restart services
service log restart; service network restart; sleep 10
 
# Log and status
logread -e netifd -e pppd
 
# Runtime configuration
pgrep -f -a ssh; pgrep -f -a pppd
ip address show; ip route show table all
ip rule show; ip -6 rule show; nft list ruleset
ssh -i ${VPN_KEY} -p ${VPN_PORT} \
${VPN_USER}@${VPN_SERV} ubus call system board
 
# Persistent configuration
uci show network; uci show firewall

PPPoSSH client

Introduction

Goals

Command-line instructions

1. Preparation

2. Key management

3. Firewall

4. Network

Testing

Troubleshooting