PPPoSSH server

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 server on OpenWrt.
Follow PPPoSSH client for client 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.

Specify configuration parameters for VPN server.

# Configuration parameters
VPN_PORT="22"

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

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

Consider VPN network as private. Assign VPN interface to LAN zone to minimize firewall setup. Allow access to VPN server from WAN zone.

# Configure firewall
uci rename firewall.@zone[0]="lan"
uci rename firewall.@zone[1]="wan"
uci del_list firewall.lan.device="ppp+"
uci add_list firewall.lan.device="ppp+"
uci -q delete firewall.pppossh
uci set firewall.pppossh="rule"
uci set firewall.pppossh.name="Allow-PPPoSSH"
uci set firewall.pppossh.src="wan"
uci set firewall.pppossh.dest_port="${VPN_PORT}"
uci set firewall.pppossh.proto="tcp"
uci set firewall.pppossh.target="ACCEPT"
uci commit firewall
/etc/init.d/firewall restart

Configure VPN service. Disable password authentication.

# Configure VPN service
uci set dropbear.@dropbear[0].Port="${VPN_PORT}"
uci set dropbear.@dropbear[0].PasswordAuth="0"
uci set dropbear.@dropbear[0].RootPasswordAuth="0"
uci commit dropbear
/etc/init.d/dropbear restart

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
/etc/init.d/log restart; /etc/init.d/dropbear restart; sleep 10
 
# Log and status
logread -e dropbear; netstat -l -n -p | grep -e dropbear
 
# Runtime configuration
pgrep -f -a dropbear; pgrep -f -a pppd
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 dropbear

PPPoSSH server

Introduction

Goals

Command-line instructions

1. Preparation

2. Key management

3. Firewall

4. VPN service

Testing

Troubleshooting