Telekom Glasfaser with Linux with dual stack and IPv6 prefix delegation

Telekom Glasfaser Internet access works very well with Linux. You have to use ppp with pppoe.

First make sure you have enabled static IPs in the Telekom Kundencenter.

The Telekom technician will install the "Glasfaser Modem". It has a external power supply and a RJ45 connector.

Connect that RJ45 to your Linux box with an ethernet cable. My interface is enp1s0f3.

The modem provides the internet access on Vlan 7, I using systemd-networkd:

# /etc/systemd/network/enp1s0f3.network
[Match]
Name=enp1s0f3

[Network]
VLAN=telekom

# /etc/systemd/network/telekom.netdev
[NetDev]
Name=telekom
Kind=vlan

[VLAN]
Id=7

install on Debian/Ubuntu the required packages:

apt-get install -y wide-dhcpv6-client ppp pppoe

to receive a IPv6 address on ppp0, you have to enable accept_ra with a ip-up.d script:

#!/bin/sh -e
# /etc/ppp/ip-up.d/ipv6 
PPP_IFACE="$1"
PPP_TTY="$2"
PPP_SPEED="$3"
PPP_LOCAL="$4"
PPP_REMOTE="$5"
PPP_IPPARAM="$6"

echo 2 > /proc/sys/net/ipv6/conf/$PPP_IFACE/accept_ra

make sure it is executable:

chmod +x /etc/ppp/ip-up.d/ipv6

The pppoe username combined: Anschlusskennung + Zugangsnummer + 0001@t-online.de

Add the combined username and the password to /etc/ppp/pap-secrects:

"AAAAAAAAAAAAAZZZZZZZZZZ001@t-online.de"  *   ""

setup a new ppp peer: /etc/ppp/peers/telekom

user AAAAAAAAAAAAAZZZZZZZZZZ001@t-online.de

pty "/usr/sbin/pppoe -I telekom -T 80 -m 1452"

# enable Ipv6, add a static prefix for fe80:: address to ensure always get the same global v6 address
+ipv6 
ipv6 ::EE:6c:aabd,

noipdefault
defaultroute

hide-password
lcp-echo-interval 20
lcp-echo-failure 3
# Override any connect script that may have been set in /etc/ppp/options.
connect /bin/true
noauth
persist
mtu 1492

noaccomp
default-asyncmap
maxfail 30
holdoff 0

perhaps you want a unit file to start the internet:

#/etc/systemd/system/ppp@.service 
[Unit]
Description=PPP link to %I
Before=network.target

[Service]
ExecStart=/usr/sbin/pppd call %I nodetach nolog

[Install]
WantedBy=multi-user.target

systemctl enable --now ppp@telekom.service

make sure your IPv6 firewall works and you allow dhcpv6 requests for IPv6 PD:

ip6tables -A INPUT -s fe80::/10 -i ppp0 -p udp -m udp --dport 546 -m comment --comment "Allow DHCPv6" -j ACCEPT

use wide-dhcpv6-client to receive a IPv6 prefix for your lan via IPv6 PD:

# /etc/default/wide-dhcpv6-client 
INTERFACES="ppp0"

# /etc/wide-dhcpv6/dhcp6c.conf 
interface ppp0 {
    send ia-pd 8;
    
};

id-assoc pd 8 {
    prefix-interface eno1 {
        sla-len 8;
        sla-id 0;
    };
    prefix-interface eno2 {
        sla-len 8;
        sla-id 1;
    };
};

profile default
{
  information-only;
};

Telekom will give you a /56 network. This wide-dhcpv6-client will add a new /64 network on your eno1 and eno2 interface. Because Telekom has a /56 network you have to add 8 bits to get a /64 for your eno1 network. (sla-len parameter).

After starting wide-dhcpv6-client the new IPv6 address will be added to your interfaces. Use radvd or dhcpd on your eno1 interface to distribute your IPv6 address to your clients.

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Telekom Glasfaser with Linux with dual stack and IPv6 prefix delegation