No IPv6 address (solved)

Installing and Using OpenWrt
1

Hi, I'm using an OpenWrt One. Reset to factory settings and only enabled Wifi with a password. No other changes to the config.
WAN port is connected to a network where a Fritz-Box provides IP addresses, both IPv4 and IPv6. Here is the status:

Bildschirmfoto 2025-06-15 um 17.08.25
Bildschirmfoto 2025-06-15 um 17.08.251932×1510 297 KB

From the routers console, I can ping IPv6:

root@OpenWrt:/etc/config# ping -6 ipv6.google.com
PING ipv6.google.com (2a00:1450:4001:830::200e): 56 data bytes
64 bytes from 2a00:1450:4001:830::200e: seq=0 ttl=119 time=18.028 ms
64 bytes from 2a00:1450:4001:830::200e: seq=1 ttl=119 time=17.122 ms
64 bytes from 2a00:1450:4001:830::200e: seq=2 ttl=119 time=16.864 ms

However, clients on the wireless network (a Mac as well es an Android phone) do not get an IPv6 address. Anybody who knew what needs to be done?

Here is my config:

root@OpenWrt:/etc/config# cat network 

config interface 'loopback'
	option device 'lo'
	option proto 'static'
	option ipaddr '127.0.0.1'
	option netmask '255.0.0.0'

config globals 'globals'
	option ula_prefix 'fdb5:949a:c640::/48'

config device
	option name 'br-lan'
	option type 'bridge'
	list ports 'eth1'

config interface 'lan'
	option device 'br-lan'
	option proto 'static'
	option ipaddr '192.168.1.1'
	option netmask '255.255.255.0'
	option ip6assign '60'

config interface 'wan'
	option device 'eth0'
	option proto 'dhcp'

config interface 'wan6'
	option device 'eth0'
	option proto 'dhcpv6'


root@OpenWrt:/etc/config# cat firewall 
config defaults
	option syn_flood	1
	option input		REJECT
	option output		ACCEPT
	option forward		REJECT
# Uncomment this line to disable ipv6 rules
#	option disable_ipv6	1

config zone
	option name		lan
	list   network		'lan'
	option input		ACCEPT
	option output		ACCEPT
	option forward		ACCEPT

config zone
	option name		wan
	list   network		'wan'
	list   network		'wan6'
	option input		REJECT
	option output		ACCEPT
	option forward		REJECT
	option masq		1
	option mtu_fix		1

config forwarding
	option src		lan
	option dest		wan

# We need to accept udp packets on port 68,
# see https://dev.openwrt.org/ticket/4108
config rule
	option name		Allow-DHCP-Renew
	option src		wan
	option proto		udp
	option dest_port	68
	option target		ACCEPT
	option family		ipv4

# Allow IPv4 ping
config rule
	option name		Allow-Ping
	option src		wan
	option proto		icmp
	option icmp_type	echo-request
	option family		ipv4
	option target		ACCEPT

config rule
	option name		Allow-IGMP
	option src		wan
	option proto		igmp
	option family		ipv4
	option target		ACCEPT

# Allow DHCPv6 replies
# see https://github.com/openwrt/openwrt/issues/5066
config rule
	option name		Allow-DHCPv6
	option src		wan
	option proto		udp
	option dest_port	546
	option family		ipv6
	option target		ACCEPT

config rule
	option name		Allow-MLD
	option src		wan
	option proto		icmp
	option src_ip		fe80::/10
	list icmp_type		'130/0'
	list icmp_type		'131/0'
	list icmp_type		'132/0'
	list icmp_type		'143/0'
	option family		ipv6
	option target		ACCEPT

# Allow essential incoming IPv6 ICMP traffic
config rule
	option name		Allow-ICMPv6-Input
	option src		wan
	option proto	icmp
	list icmp_type		echo-request
	list icmp_type		echo-reply
	list icmp_type		destination-unreachable
	list icmp_type		packet-too-big
	list icmp_type		time-exceeded
	list icmp_type		bad-header
	list icmp_type		unknown-header-type
	list icmp_type		router-solicitation
	list icmp_type		neighbour-solicitation
	list icmp_type		router-advertisement
	list icmp_type		neighbour-advertisement
	option limit		1000/sec
	option family		ipv6
	option target		ACCEPT

# Allow essential forwarded IPv6 ICMP traffic
config rule
	option name		Allow-ICMPv6-Forward
	option src		wan
	option dest		*
	option proto		icmp
	list icmp_type		echo-request
	list icmp_type		echo-reply
	list icmp_type		destination-unreachable
	list icmp_type		packet-too-big
	list icmp_type		time-exceeded
	list icmp_type		bad-header
	list icmp_type		unknown-header-type
	option limit		1000/sec
	option family		ipv6
	option target		ACCEPT

config rule
	option name		Allow-IPSec-ESP
	option src		wan
	option dest		lan
	option proto		esp
	option target		ACCEPT

config rule
	option name		Allow-ISAKMP
	option src		wan
	option dest		lan
	option dest_port	500
	option proto		udp
	option target		ACCEPT


### EXAMPLE CONFIG SECTIONS
# do not allow a specific ip to access wan
#config rule
#	option src		lan
#	option src_ip	192.168.45.2
#	option dest		wan
#	option proto	tcp
#	option target	REJECT

# block a specific mac on wan
#config rule
#	option dest		wan
#	option src_mac	00:11:22:33:44:66
#	option target	REJECT

# block incoming ICMP traffic on a zone
#config rule
#	option src		lan
#	option proto	ICMP
#	option target	DROP

# port redirect port coming in on wan to lan
#config redirect
#	option src			wan
#	option src_dport	80
#	option dest			lan
#	option dest_ip		192.168.16.235
#	option dest_port	80
#	option proto		tcp

# port redirect of remapped ssh port (22001) on wan
#config redirect
#	option src		wan
#	option src_dport	22001
#	option dest		lan
#	option dest_port	22
#	option proto		tcp

### FULL CONFIG SECTIONS
#config rule
#	option src		lan
#	option src_ip	192.168.45.2
#	option src_mac	00:11:22:33:44:55
#	option src_port	80
#	option dest		wan
#	option dest_ip	194.25.2.129
#	option dest_port	120
#	option proto	tcp
#	option target	REJECT

#config redirect
#	option src		lan
#	option src_ip	192.168.45.2
#	option src_mac	00:11:22:33:44:55
#	option src_port		1024
#	option src_dport	80
#	option dest_ip	194.25.2.129
#	option dest_port	120
#	option proto	tcp

root@OpenWrt:/etc/config# cat dhcp 

config dnsmasq
	option domainneeded '1'
	option boguspriv '1'
	option filterwin2k '0'
	option localise_queries '1'
	option rebind_protection '1'
	option rebind_localhost '1'
	option local '/lan/'
	option domain 'lan'
	option expandhosts '1'
	option nonegcache '0'
	option cachesize '1000'
	option authoritative '1'
	option readethers '1'
	option leasefile '/tmp/dhcp.leases'
	option resolvfile '/tmp/resolv.conf.d/resolv.conf.auto'
	option nonwildcard '1'
	option localservice '1'
	option ednspacket_max '1232'
	option filter_aaaa '0'
	option filter_a '0'

config dhcp 'lan'
	option interface 'lan'
	option start '100'
	option limit '150'
	option leasetime '12h'
	option dhcpv4 'server'
	option dhcpv6 'server'
	option ra 'server'
	option ra_slaac '1'
	list ra_flags 'managed-config'
	list ra_flags 'other-config'

config dhcp 'wan'
	option interface 'wan'
	option ignore '1'

config odhcpd 'odhcpd'
	option maindhcp '0'
	option leasefile '/tmp/hosts/odhcpd'
	option leasetrigger '/usr/sbin/odhcpd-update'
	option loglevel '4'
2

Does the Fritzbox do prefix delegation to down stream routers?

3

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I guess we are talking about this.
That's how it is configured right now. I don't understand why the third option says: "devices in home network will be assigned an IPv6 address via DHCPv6".
I currently get an IPv6 address on all devices although option 1 is selected.
So which one is the appropriate one?

4

Okay, that did the trick. I changed to option 2 "DNS-Server und IPv6-Präfix (IA_PD) zuweisen" and now I do get IPv6 address from OpenWrt.
Thanks very much, Bernd.
If it's not asked too much: What would I get if I picked option 3? What's the difference?

5

Try the last one, your router should get a prefix delegated which your router can use for its lan clients

6

Your wan will also get a global ipv6 address

But I am not an authority on IPv6 (@_bernd is)

7

@robertaramar
Yes Option 3. In case you still have clients connected to the Fritzbox.

You could, if no clients are connected to the Fritzbox, use option 2.
Then your OpenWrt would only use the link local address but might has no global IPv6 address.

Currently with your OpenWrt defaults, how large is the delegated prefix now, when using option 2.
And could you test option 3 and a reboot of the openwrt and also a Network restart of one of your clients on OpenWrt?

Edit ps. I ask because I wanted to know what prefix size the Fritzbox delegates...

1 Like
8

It's kind of strange.

  1. Yes, my clients on the Fritz box don't get IPv6 with option 3
  2. Yes, with option 3 I now see IPv6 address outside from both networks
  3. However, i don't see these IPv6 leases on my openwrt any longer.

See screenshots attached. First status is with option 3 (no DHCPv6 leases) the other one with option 2 (with DHCPv6 leases)

Funnily, ifconfig.io stille reports an IPv6 address although i don't see the lease on openwrt.

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