Best Practices for Configuring IPv4 and IPv6 Dual Stack in a PPPoE Access Network

When you use static PPPoE interfaces with NDRA, the prefix configured for router advertisement must match the source address specified under family inet6 in the logical pp0 interface configuration. If these values do not match, the prefix is not advertised correctly.

For example:

[edit protocols router-advertisement]
interface pp0.2004 {
    prefix 2001:db8:2040:2004::/64;
}

[edit interface pp0]
unit 2004 {
    family inet6 {
        address 2001:db8:2040:2004::10.1.1.1/64;
    }
}

To view the prefix in the ICMPv6 packet, use the monitor traffic interface pp0.xxx extensive command. If the prefix is missing, make sure that there is not a mismatch between the family inet6 address configured for the interface and the prefix configured for the interface in the router advertisement configuration.

When you use DHCPv6 prefix delegation over a PPPoE access network, you need to enable unnumbered addressing in the family inet6 configuration.

For dynamic PPPoE interfaces, enable unnumbered addressing in the dynamic profile. For example:

[edit dynamic-profiles]
PPPoE-dyn-ipv4v6-dhcp {
    interfaces {
        pp0 {
            unit "$junos-interface-unit" {
                . . .
                family inet6 {
                    unnumbered-address lo0.0;
                }
            }
        }
    }
}

For static PPPoE interfaces, enable unnumbered addressing in the interface configuration. For example:

[edit interface pp0]
unit 2004 {
    family inet6 {
    unnumbered-address lo0.0;

When you use NDRA, always set the IPv6 internet address in dynamic profiles to the $junos-ipv6-address predefined variable. This variable is replaced with the IPv6 address of the interface used for router advertisements.

[edit dynamic-profiles]
dyn-v4v6-ndra {
    interfaces {
        pp0 {
            unit "$junos-interface-unit" {
                family inet6 {
                    address "$junos-ipv6-address ";
                }
            }
        }
    }
}

The IPv6 address configuration for logical interfaces in PPPoE dynamic profiles when you are using DHCPv6 depends on whether or not you are using routing instances.

If you are using routing instances, use the $junos-loopback-interface predefined variable for the IPv6 address. For example:

[edit dynamic-profiles]
dyn-v4v6-ri {
    routing-instances {
        "$junos-routing-instance" {
            interface "$junos-interface-name";
        }
    }
    interfaces {
        pp0 {
            unit "$junos-interface-unit" {
                family inet6 {
                    unnumbered-address "$junos-loopback-interface";
                }
            }
        }
    }
}

If you are not using routing instances, use the unnumbered address for the IPv6 address. The unnumbered address enables the local address to be derived from the specified interface and allows IP processing on the interface without assigning an explicit IP address to the interface. For example:

[edit dynamic-profiles]
dyn-v4v6-ndra {
    interfaces {
        pp0 {
            unit "$junos-interface-unit" {
                pppoe-options {
                    underlying-interface "$junos-underlying-interface";
                    server;
                }
                family inet6 {
                    unnumbered-address lo0.0;
                }
            }
        }
    }
}

The IPv4 address configuration for logical interfaces in PPPoE dynamic profiles depends on whether or not you are using routing instances.

If you are using routing instances, use the $junos-loopback-interface variable for the IPv6 address.

[edit dynamic-profiles]
dyn-v4v6-ri {
    routing-instances {
        "$junos-routing-instance" {
            interface "$junos-interface-name";
        }
    }
    interfaces {
        pp0 {
            unit "$junos-interface-unit" {
                family inet {
                    unnumbered-address "$junos-loopback-interface";
                }
            }
        }
    }
}

If you are not using routing instances, use the unnumbered address for the IPv6 address. The unnumbered address enables the local address to be derived from the specified interface and allows IP processing on the interface without assigning an explicit IP address to the interface.

[edit dynamic-profiles]
dyn-v4v6-ndra {
    interfaces {
        pp0 {
            unit "$junos-interface-unit" {
                pppoe-options {
                    underlying-interface "$junos-underlying-interface";
                    server;
                }
                family inet {
                    unnumbered-address lo0.0;
                }
            }
        }
    }
}

In most cases PPPoE is used to authenticate subscribers in a PPPoE access network. However, if you wish to use DHCP to perform the authentication, do not configure subscriber authentication at the [edit system services dhcp-local-server] or the [edit system services dhcp-local-server dhcpv6] hierarchy levels. Instead configure subscriber authentication at the [edit system services dhcp-local-server dhcpv6 group] hierarchy level. For example:

[edit system services dhcp-local-server dhcpv6]
group v6-dhcp-client {
    authentication {
        password $ABC123;
        username-include {
            user-prefix StaticUser;
        }
    }
}