PPPoE Server Configuration Guide

Introduction

This guide provides a step-by-step tutorial for configuring the PPPoE Server capability on the Asterfusion Open Intelligent Gateway running AsterNOS-VPP.

By following this guide, you will transform a standard Layer 3 gateway into a high-performance Broadband Network Gateway (vBNG) capable of handling client dial-ups, centralized AAA billing, and internet access via NAT.

What This Guide Will Accomplish

This document is structured to reflect real-world enterprise deployment priorities:

• Scenario 1: Enterprise RADIUS Integration (Main Deployment) We will configure the gateway to act as a vBNG access node, integrated with an external RADIUS server for centralized Authentication, Authorization, and Accounting (AAA). This phase covers both local IP allocation and fully centralized RADIUS IP pool management.
• Scenario 2: Standalone Gateway Mode (Local Auth & NAT) Configuring the gateway to rely on its internal local database for dial-in access and enabling Source NAT (SNAT). This is ideal for small, isolated networks or as an emergency fallback.

Scenario 1

Network Topology Plan

Target Configuration Plan

Device/Interface	IP Address/Subnet	Role
AsterNOS (Eth1)	192.168.200.166/24	WAN Uplink(Route to RADIUS & Core Network)
AsterNOS (Eth2)	N/A (Layer 2 PPPoE)	LAN Interface(PPPoE Dial-in Port)
RADIUS Server	192.168.200.253/24	Centralized AAA Server(FreeRADIUS)
Dial-in Client PC	192.168.100.x/24	PPPoE Client

Phase 1: Baseline Setup (Local Pool IP Allocation)

In this phase, we establish an enterprise-grade vBNG architecture. To ensure a smooth deployment, we will build this in two stages:

1. Baseline Setup: Centralized RADIUS authentication combined with AsterNOS local IP allocation.
2. Advanced Setup: Fully centralized architecture where RADIUS handles both authentication and dynamic IP allocation.

Base Network & RADIUS Global Configuration

sonic# configure terminal
 # 1. Configure the WAN Interface (Required to reach the RADIUS server)
sonic(config)# interface ethernet 1
sonic(config-if-1)# ip address 192.168.200.166/24
sonic(config-if-1)# exit
 # 2. Define Default Route to Core Network
sonic(config)# ip route 0.0.0.0/0 192.168.200.1
 # 3. Define the Global RADIUS server.
CRITICAL: The 'mode pppoe' attribute must be configured FIRST.
sonic(config)# radius server 192.168.200.253 mode pppoe
sonic(config)# radius server 192.168.200.253 auth-type chap
sonic(config)# radius server 192.168.200.253 passkey aster123

Configure the PPPoE Server

In our baseline setup, AsterNOS relies on RADIUS for user authentication but handles IP address distribution locally.

1. Enable PPPoE Server globally
sonic(config)# pppoe-server enable
 # 2. Create the local IP pool for dial-in clients
sonic(config)# ip-pool pppoe-pool
sonic(config-ip-pool)# ip-range 192.168.100.10 192.168.100.254
sonic(config-ip-pool)# exit
 # 3. Enter PPPoE Server instance 1
sonic(config)# interface pppoe-server 1
sonic(config-if-pppoeserver-1)# service-name pppoe-enterprise
sonic(config-if-pppoeserver-1)# ac-name pppoe-server-1
 # 4. Bind RADIUS for Authentication and Accounting
sonic(config-if-pppoeserver-1)# ppp chap radius-server 192.168.200.253
sonic(config-if-pppoeserver-1)# nas-ip 192.168.200.166
 # 5. Set Virtual Gateway IP and bind the local pool
sonic(config-if-pppoeserver-1)# local-ip 192.168.100.1 255.255.255.0
sonic(config-if-pppoeserver-1)# remote-ip-pool pppoe-pool
 # 6. Network Parameters
sonic(config-if-pppoeserver-1)# dns-server 8.8.8.8
sonic(config-if-pppoeserver-1)# accept-blank-service enable
sonic(config-if-pppoeserver-1)# exit
 # 7. Bind to physical LAN port
sonic(config)# interface ethernet 2
sonic(config-if-2)# pppoe-server 1
sonic(config-if-2)# exit

Note

-If usingaccept-any-service enable: The service-name does not need to be configured on either the server or the client.

-If usingaccept-blank-service enable: The service-namemustbe configured on the server, and the client mustnot configure it (leave it blank).

FreeRADIUS Server Setup

Deploy a lightweight FreeRADIUS configuration focused strictly on AAA, without the complexity of IP pool management.

• Install FreeRADIUS

sudo apt-get update
sudo apt-get install freeradius -y

• Configure the NAS Client (AsterNOS Gateway)

sudo nano /etc/freeradius/3.0/clients.conf

client AsterNOS-Gateway {
    ipaddr = 192.168.200.166
    secret = aster123
}

• Create the User Profile

sudo nano /etc/freeradius/3.0/users

"radiususer" Cleartext-Password := "radius123"
        Service-Type = Framed-User,
        Framed-Protocol = PPP

• Restart Service

Note

On Ubuntu/Debian systems, FreeRADIUS starts automatically upon installation. A restart is required to load the newly configured clients and users.

sudo systemctl restart freeradius

Phase2: Advanced Integration (Centralized RADIUS IP Allocation)

Once the baseline authentication is verified, enterprise architectures typically migrate IP allocation to the RADIUS server. This consolidates user management and billing into a single pane of glass.

To upgrade from the Baseline to the Centralized architecture, follow these Delta steps:

Unbind the Local Pool on AsterNOS

Shift the allocation responsibility away from the gateway.

sonic# configure terminal
sonic(config)# interface pppoe-server 1
sonic(config-if-pppoeserver-1)# no remote-ip-pool pppoe-pool
sonic(config-if-pppoeserver-1)# exit

Configure the RADIUS IP Pool

sudo nano /etc/freeradius/3.0/mods-available/ippool

ippool main_pool {
    range_start = 192.168.100.10
    range_stop = 192.168.100.254
    netmask = 255.255.255.0

    # Keep the following default parameters unchanged
    filename = ${db_dir}/db.ippool
    ip_index = ${db_dir}/db.ipindex
    override = no
    maximum_timeout = 0
}

Enable the module

sudo ln -s /etc/freeradius/3.0/mods-available/ippool /etc/freeradius/3.0/mods-enabled/

Activate IP Pool in Accounting & Post-Auth

sudo nano /etc/freeradius/3.0/sites-enabled/default

In the accounting { ... } block, add:

accounting {
        detail
        unix
        main_pool  # <--- Add this line
        exec
        # ...
}

In the post-auth { ... } block, add:

post-auth {
        exec
        main_pool  # <--- Add this line
        # ...
}

Update User Profile & Apply Changes

sudo nano /etc/freeradius/3.0/users

"radiususer" Cleartext-Password := "radius123", Pool-Name := "main_pool"
        Service-Type = Framed-User,
        Framed-Protocol = PPP

sudo systemctl restart freeradius

Phase 1 & 2 Verification

After completing the configuration and restarting the RADIUS service, follow these steps to verify that the PPPoE session is successfully established:

1. Client Dial-in: Create a PPPoE connection on the client PC and dial in using your username and password.
2. Check Session Status: Once successfully connected, execute the following command to view real-time session information.

sonic# show pppoe-session

Expected Output:

 Id  Iface      SessionId  RemoteMac          RemoteIp       LocalIp        LocalIf    PppoeServer     Uptime
---- ---------  -----------  -----------------  -------------  -------------  ---------  --------------  --------
   0 Ethernet3          384  00:e0:4c:68:06:0d  192.168.100.10 192.168.100.1  ppp0       pppoe-server-1  0:00:37

Note

Under the Scenario 1configuration, the client can successfully dial in and establish a network connection. To enable internet access, please ensure that the core network has the appropriate NAT policies configured, or refer toScenario 2** to enable local SNAT on AsterNOS.

Scenario

This section provides the complete, standalone configuration required to set up the PPPoE server using AsterNOS’s internal database for authentication and local IP pool for address allocation.

Caution

Important:

AsterNOS does not support automatic fallback to the local database if a RADIUS server is configured but unreachable. You must manually remove the RADIUS server binding before local credentials can take effect.

Configure the PPPoE Server

1. Enable PPPoE Server globally
sonic# configure terminal
sonic(config)# pppoe-server enable
 # 2. Create the local IP pool for dial-in clients
sonic(config)# ip-pool pppoe-pool
sonic(config-ip-pool)# ip-range 192.168.100.10 192.168.100.254
sonic(config-ip-pool)# exit
 # 3. Enter PPPoE Server instance 1
sonic(config)# interface pppoe-server 1
sonic(config-if-pppoeserver-1)# service-name pppoe-enterprise
sonic(config-if-pppoeserver-1)# ac-name pppoe-server-1

sonic(config-if-pppoeserver-1)# ppp chap username testuser 123456
sonic(config-if-pppoeserver-1)# nas-ip 192.168.200.166
 # 5. Set Virtual Gateway IP and bind the local pool
sonic(config-if-pppoeserver-1)# local-ip 192.168.100.1 255.255.255.0
sonic(config-if-pppoeserver-1)# remote-ip-pool pppoe-pool
 # 6. Network Parameters
sonic(config-if-pppoeserver-1)# dns-server 8.8.8.8
sonic(config-if-pppoeserver-1)# accept-blank-service enable
sonic(config-if-pppoeserver-1)# exit
 # 7. Bind to physical LAN port
sonic(config)# interface ethernet 2
sonic(config-if-ethernet2)# pppoe-server 1
sonic(config-if-ethernet2)# exit

Enable SNAT for Internet Access

To allow the locally authenticated PPPoE clients (e.g., 192.168.100.x) to browse the public internet, you must translate their private IPs to the WAN interface’s public/uplink IP.

1. Enable the NAT engine globally
sonic(config)# nat enable
 # 2. Define a NAT pool using the WAN uplink IP (192.168.200.166)
sonic(config)# nat pool wan-pool 192.168.200.166
 # 3. Bind the pool to masquerade all outbound routed traffic
sonic(config)# nat binding bind-wan wan-pool
 # 4. Apply NAT zone to the WAN interface
sonic(config)# interface ethernet 1
sonic(config-if-1)# nat-zone 1
sonic(config-if-1)# exit

Verification

After completing the configuration, follow these steps to verify that the PPPoE session is successfully established:

1. Client Dial-in: Create a PPPoE connection on the client PC and dial in using your username and password.
2. Check Session Status: Once successfully connected, execute the following command to view real-time session information.

sonic# show pppoe-session

Expected Output:

 Id  Iface      SessionId  RemoteMac          RemoteIp       LocalIp        LocalIf    PppoeServer     Uptime
---- ---------  -----------  -----------------  -------------  -------------  ---------  --------------  --------
   0 Ethernet3          384  00:e0:4c:68:06:0d  192.168.100.10 192.168.100.1  ppp0       pppoe-server-1  0:00:37

Conclusion

This guide has verified the comprehensive PPPoE Server capabilities of AsterNOS, transforming a standard gateway into a high-performance vBNG. The completed scenarios demonstrate its deployment flexibility, seamlessly supporting both enterprise centralized RADIUS integration and standalone operations with local authentication and NAT.