IPv6 over PPPoE

I have a PPPoE link and some addresses. IPv4 addresses work fine. IPv6 not at all. I found out I had to add +ipv6 in ppp/options. If I ping ff02::1%ppp0 I only get replies from two fe80:: addresses, one was automatically assigned to the interface and the other one is reported as *peer* by ip address. The routable address I assigned doesn't play. I found a [traceroute test](https://tools.keycdn.com/traceroute) on the Internet. It cannot reach the address that my ISP assigned me, 2a02:29e1:300:e900::1. It shows some loops, which, if it were IPv4, I'd definitely classify as router misconfiguration. My ISP says there are no anomalies on their IPv6, which is on the same BRAS as mine. I asked again and they reassured me everything is fine on their side, and they cannot help me on a custom configuration. (Custom because I avoided installing a router). I tried and installed radvd but it doesn't seem to do anything interesting —indeed, radvdump shows continuous work on another interface, which has no routable IPv6 address, although I tried to disable it by setting AdvSendAdvert off. When I try traceroute, I get no response. I issue, for example, sudo traceroute -6 -n -i ppp0 -I 2a02:29e0:404::172:162. tcpdump -i ppp0 ip6 shows only echo requests going out. I use -I because I allow ICMP access. Yet, after attempting traceroute, ip6tables-save -c reports an increased amount of dropped input packets:

:INPUT DROP [259:20898]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [374:39007]
[0:0] -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
[0:0] -A INPUT -p tcp -m conntrack --ctstate NEW -m multiport --dports 80,443 -j ACCEPT
[371:25320] -A INPUT -p ipv6-icmp -j ACCEPT

My only previous experience with IPv6 was using a tunnel. It had been enough to assign the addresses and it worked without problems. As something must be wrong with routing, here's radvd's config:

interface ppp0
{
	IgnoreIfMissing off;
	AdvSendAdvert on;
	prefix 2a02:29e1:300:e900::/64
	{
	};
};

interface eth1r
{
	AdvSendAdvert off;
};

Is it the right tool at all? **Edit**: IPv6 routes:

north:~$ ip -6 r l
2a02:29e1:300:e900::/64 dev ppp0 proto kernel metric 256 pref medium
fe80::f3:6aec dev ppp0 proto kernel metric 256 pref medium
fe80::51c9:88dc:1c75:9a51 dev ppp0 proto kernel metric 256 pref medium
fe80::/64 dev eth0r.100 proto kernel metric 256 pref medium
fe80::/64 dev eth0r proto kernel metric 256 pref medium
fe80::/64 dev eth1r proto kernel metric 256 pref medium
fe80::/64 dev eth2r proto kernel metric 256 pref medium
default dev ppp0 metric 1024 pref medium

Here eth0r.100 is the 802.1Q interface which starts ppp0. eth1r is a backup natted wan which should stay IPv4-only. eth2r is a lan, which could use IPv6 eventually (perhaps radvd can be useful in that case?). As for the **routing loop**, the traceroute test mentioned above runs from ten cities around the world, and none of them reaches my interface; all of them fall into the same loop reported by [Bib](https://unix.stackexchange.com/users/433674/bib) , around the following five nodes:

2a00:6d42::1:0:1:36       Aruba S.p.A. (sometimes ???)
2a00:6d42:0:2:5::12            "             "
2a02:29e1::a              Seflow s.r.l. (my ISP)
2a02:29e0:109:ff00::5          "
2a02:29e0:255::2               "
2001:7f8:c5::a503:1034:1  Samer Abdel-Hafez (sometimes ???)

The bottom one, from Amsterdam, points back to Aruba and the loop starts over again. Can that be caused by a lack of advertising on my side? But then, how could I be able to advertise anything if I don't get any IPv6 reply from ppp0?