PPPoE

PPPoE is a network protocol for encapsulating PPP frames inside Ethernet frames. It appeared in 1999, in the context of the boom of DSL as the solution for tunneling packets over the DSL connection to the ISPs IP network, and from there to the rest of the Internet. A 2005 networking book noted that “Most DSL providers use PPPoE, which provides authentication, encryption, and compression.” Typical use of PPPoE involves leveraging the PPP facilities for authenticating the user with a username and password, predominately via the PAP protocol and less often via CHAP.

Operating Modes

VyOS supports setting up PPPoE in two different ways to a PPPoE internet connection. This is due to most ISPs provide a modem that is also a wireless router.

Home Users

In this method, the DSL Modem/Router connects to the ISP for you with your credentials preprogrammed into the device. This gives you an RFC 1918 address, such as 192.168.1.0/24 by default.

For a simple home network using just the ISP’s equipment, this is usually desirable. But if you want to run VyOS as your firewall and router, this will result in having a double NAT and firewall setup. This results in a few extra layers of complexity, particularly if you use some NAT or tunnel features.

Business Users

In order to have full control and make use of multiple static public IP addresses, your VyOS will have to initiate the PPPoE connection and control it. In order for this method to work, you will have to figure out how to make your DSL Modem/Router switch into a Bridged Mode so it only acts as a DSL Transceiver device to connect between the Ethernet link of your VyOS and the phone cable. Once your DSL Transceiver is in Bridge Mode, you should get no IP address from it. Please make sure you connect to the Ethernet Port 1 if your DSL Transeiver has a switch, as some of them only work this way.

Once you have an Ethernet device connected, i.e. eth0, then you can configure it to open the PPPoE session for you and your DSL Transceiver (Modem/Router) just acts to translate your messages in a way that vDSL/aDSL understands.

Configuration

set interfaces pppoe <interface> access-concentrator <name>

Use this command to restrict the PPPoE session on a given access concentrator. Normally, a host sends a PPPoE initiation packet to start the PPPoE discovery process, a number of access concentrators respond with offer packets and the host selects one of the responding access concentrators to serve this session.

This command allows you to select a specific access concentrator when you know the access concentrators <name>.

set interfaces pppoe <interface> authentication user <username>
Use this command to set the username for authenticating with a remote PPPoE endpoint. Authentication is optional from the system’s point of view but most service providers require it.
set interfaces pppoe <interface> authentication password <password>
Use this command to set the password for authenticating with a remote PPPoE endpoint. Authentication is optional from the system’s point of view but most service providers require it.
set interfaces pppoe <interface> connect-on-demand

Enables or disables on-demand PPPoE connection on a PPPoE unit.

Use this command to instruct the system to establish a PPPoE connections automatically once traffic passes through the interface. A disabled on-demand connection is established at boot time and remains up. If the link fails for any reason, the link is brought back up immediately.

Enabled on-demand PPPoE connections bring up the link only when traffic needs to pass this link. If the link fails for any reason, the link is brought back up automatically once traffic passes the interface again. If you configure an on-demand PPPoE connection, you must also configure the idle timeout period, after which an idle PPPoE link will be disconnected. A non-zero idle timeout will never disconnect the link after it first came up.

set interfaces pppoe <interface> default-route

Use this command to specify whether to automatically add a default route pointing to the endpoint of the PPPoE when the link comes up. The default route is only added if no other default route already exists in the system.

default: A default route to the remote endpoint is automatically added when the link comes up (i.e. auto).

set interfaces pppoe <interface> description
Assign given <description> to interface. Description will also be passed to SNMP monitoring systems.
set interfaces pppoe <interface> disable
Disable given <interface>. It will be placed in administratively down (A/D) state.
set interfaces pppoe <interface> idle-timeout <time>

Use this command to set the idle timeout interval to be used with on-demand PPPoE sessions. When an on-demand connection is established, the link is brought up only when traffic is sent and is disabled when the link is idle for the interval specified.

If this parameter is not set or 0, an on-demand link will not be taken down when it is idle and after the initial establishment of the connection. It will stay up forever.

set interfaces pppoe <interface> local-address <address>
Use this command to set the IP address of the local endpoint of a PPPoE session. If it is not set it will be negotiated.
set interfaces pppoe <interface> mtu <mtu>
Configure MTU on given <interface>. It is the size (in bytes) of the largest ethernet frame sent on this link.
set interfaces pppoe <interface> no-peer-dns
Use this command to not install advertised DNS nameservers into the local system.
set interfaces pppoe <interface> remote-address <address>
Use this command to set the IP address of the remote endpoint of a PPPoE session. If it is not set it will be negotiated.
set interfaces pppoe <interface> service-name <name>
Use this command to specify a service name by which the local PPPoE interface can select access concentrators to connect with. It will connect to any access concentrator if not set.
set interfaces pppoe <interface> source-interface <source-interface>
Use this command to link the PPPoE connection to a physical interface. Each PPPoE connection must be established over a physical interface. Interfaces can be regular Ethernet interfaces, VIFs or bonding interfaces/VIFs.

IPv6

set interfaces pppoe <interface> ipv6 enable
Use this command to enable IPv6 support on this PPPoE connection.
set interfaces pppoe <interface> ipv6 address autoconf
Use this command to enable acquisition of IPv6 address using stateless autoconfig (SLAAC).

Operation

show interfaces pppoe <interface>

Show detailed information on given <interface>

[email protected]:~$ show interfaces pppoe pppoe0
pppoe0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1492 qdisc pfifo_fast state UNKNOWN group default qlen 3
    link/ppp
    inet 192.0.2.1 peer 192.0.2.255/32 scope global pppoe0
       valid_lft forever preferred_lft forever

    RX:  bytes    packets     errors    dropped    overrun      mcast
    7002658233    5064967          0          0          0          0
    TX:  bytes    packets     errors    dropped    carrier collisions
     533822843    1620173          0          0          0          0
show interfaces pppoe <interface> log
Displays log information for a PPPoE interface.
show interfaces pppoe <interface> queue

Displays queue information for a PPPoE interface.

[email protected]:~$ show interfaces pppoe pppoe0 queue
qdisc pfifo_fast 0: root refcnt 2 bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
 Sent 534625359 bytes 1626761 pkt (dropped 62, overlimits 0 requeues 0)
 backlog 0b 0p requeues 0

Connect/Disconnect

disconnect interface <interface>
Test disconnecting given connection-oriented interface. <interface> can be pppoe0 as example.
connect interface <interface>
Test connecting given connection-oriented interface. <interface> can be pppoe0 as example.

Example

Requirements:

  • Your ISPs modem is connected to port eth0 of your VyOS box.
  • No VLAN tagging required by your ISP.
  • You need your PPPoE credentials from your DSL ISP in order to configure this. The usual username is in the form of name@host.net but may vary depending on ISP.
  • The largest MTU size you can use with DSL is 1492 due to PPPoE overhead. If you are switching from a DHCP based ISP like cable then be aware that things like VPN links may need to have their MTU sizes adjusted to work within this limit.
  • With the default-route option set to auto, VyOS will only add the default gateway you receive from your DSL ISP to the routing table if you have no other WAN connections. If you wish to use a dual WAN connection, change the default-route option to force.
  • With the name-server option set to none, VyOS will ignore the nameservers your ISP sens you and thus you can fully rely on the ones you have configured statically.

Note

Syntax has changed from VyOS 1.2 (crux) and it will be automatically migrated during an upgrade.

set interfaces pppoe pppoe0 default-route 'auto'
set interfaces pppoe pppoe0 mtu 1492
set interfaces pppoe pppoe0 authentication user 'userid'
set interfaces pppoe pppoe0 authentication password 'secret'
set interfaces pppoe pppoe0 source-interface 'eth0'

You should add a firewall to your configuration above as well by assigning it to the pppoe0 itself as shown here:

set interfaces pppoe pppoe0 firewall in name NET-IN
set interfaces pppoe pppoe0 firewall local name NET-LOCAL
set interfaces pppoe pppoe0 firewall out name NET-OUT

VLAN Example

Some recent ISPs require you to build the PPPoE connection through a VLAN interface. One of those ISPs is e.g. Deutsche Telekom in Germany. VyOS can easily create a PPPoE session through an encapsulated VLAN interface. The following configuration will run your PPPoE connection through VLAN7 which is the default VLAN for Deutsche Telekom:

set interfaces pppoe pppoe0 default-route 'auto'
set interfaces pppoe pppoe0 mtu 1492
set interfaces pppoe pppoe0 authentication user 'userid'
set interfaces pppoe pppoe0 authentication password 'secret'
set interfaces pppoe pppoe0 source-interface 'eth0.7'