Vodafone-Germany with PPPoE and Dual-Stack

Installing and Using OpenWrt
1

What is the best way to set up Vodafone-Dsl with DualStack? Does it work out of the box with openwrt? I made it work for me but i seems too complicate.

I noticed with Vodafone-DSL you get 1 ipv4 and a /56 ipv6 prefix - but not like most other providers (Vodafone-Docsis, Telekom Germany) a separate "router ip" outside the prefix.
I'm using an external modem which sets vlan 7.

  • The PPPOE inteface ("dsl") of openwrt dos not connect until "Obtain IPv6 address" is disabled! It does not mater what i configure, this interface never gets the PD. Also it does not add any other dynamic interfacers
  • So I added a 2nd interface DHCPv6 ("dslpd") which does also not get an IPv6 but the Prefix. An ip of this prefix could not added to the interface itself
  • So I added a 3rd interface DHCPv6 ("dsl6") which has PD disabled but gets an IPv6 of this prefix

grafik
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This works fine as Dual-Stack for all clients in the lan. nat6 is used, no other external ipv6 are assigned.

Openwrt does not correct recognizes this config and shows on the overview page only ipv4:

grafik

Also i notices "random" ipv6 assignment of openwrt does always randomize only the last 64 bit of the ip, even it is a /56 subnet

grafik
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From ipv6-test.com :

grafik
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Any ideas how to make this more simple and automatic?

Big disadvantage of this all: After a reboot of the Openwrt router (and a connection reconnect?), i have manually restart the "dslpd" device because it does not geta prefix automatically :frowning:

1 Like
2

So are you using nat6 intentionally?

My PPPoE Dual Stack config uses an alias interface for the DHCPv6 client, that receives a /48 from my ISP. My LAN interface takes a /64 of that and LAN clients get a public IPv6 address using SLAAC.

3

I have at home a Telekom Germany DSL connection, and with this Openwrt also creates automatically a dynamic "dsl6" interface. Maybe the Openwrt automatic does not work because of the missing (telekom has one) ipv6 outside the perfix? I dont know the internal things of Openwrt

Here is what a Fritzbox shows when it completely maintains the Vodafone connection:


0: name internet (attached, active internet)
0: sync_group: sync_dsl
0: iface ptm0 PPPoE/26/dsl mm:mm:mm:mm:mm:mm stay online 1 vlan 7 prio 0 (prop: default internet) (prop6: default internet)
0: IPv6: automatic (ia_pd)
0: IPv6: connected since 2024-01-06 11:29:38 (setup time 5 secs) (connect cnt 1)
0: IPv6: address 2a00:1f:xxxx:3900:yyyy:yyyy:yyyy:yyyy/64 valid 7086 prefered 3486
0: IPv6: prefix 2a00:1f:xxxx:3900::/56 valid 7086 prefered 3486 (first used)
0: IPv6: mtu 1492
0: IPv6: dns 2a01:860::53 valid 7086 (dhcp)
0: IPv6: dns 2a01:860::153 valid 7086 (dhcp)
0: IPv4: native
0: IPv4: connected since 2024-01-06 11:29:33 (setup time 0 secs) (connect cnt 1)
0: IPv4: disconnect prevention disabled
0: IPv4: ip 84.63.zz.zz peer 84.59.211.1 mtu 1492
0: IPv4: masqaddr 84.63.zz.zz
0: IPv4: dns kk.kk.kk.nn kk.kk.kk.mm
0: route 84.63.zz.zz/32 protocol iface
0: route kk.kk.kk.nn/32 protocol dns
0: route kk.kk.kk.mm/32 protocol dns
0: acname ABCDEFGHIJK

I like nat6, i should not matter here but i wanted it to mentioned