Posted: Wed Apr 20, 2022 4:51 Post subject: R7000 lost Comcast IPv6 WAN recently
Hello,
I have recently lost WAN IPv6 address on my router, it happened recently when I rebooted the router and power cycled the modem. In the past whenever ddwrt has troubles acquiring ipv6 all I had to do is power cycle the modem and that would fix it.
I recently noticed that my public/WAN IPv4 address changed as well, that was a surprise, I used to have my old IP for years, I'm still running the same R7000 router so my MAC address hasn't changed. I'm on v3.0-r46446 std (04/24/21) firmware if that matters.
Apr 19 23:36:58 R7000 daemon.debug radvd[9872]: timer_handler called for br0
Apr 19 23:36:58 R7000 daemon.debug radvd[9872]: sending RA to ff02::1 on br0 (fe80::deef:9ff:fe97:2219), 4 options (using 88/1210 bytes)
Apr 19 23:36:58 R7000 daemon.debug radvd[9872]: br0 next scheduled RA in 9.02707 second(s)
Apr 19 23:36:58 R7000 daemon.debug radvd[9872]: polling for 9.027 second(s), next iface is br0
Apr 19 23:36:58 R7000 daemon.debug radvd[9872]: br0 recvmsg len=88
Apr 19 23:36:58 R7000 daemon.debug radvd[9872]: br0 received a packet
Apr 19 23:36:58 R7000 daemon.debug radvd[9872]: br0 received RA from: fe80::deef:9ff:fe97:2219 (myself)
Apr 19 23:36:58 R7000 daemon.debug radvd[9872]: polling for 9.026 second(s), next iface is br0
Apr 19 23:37:02 R7000 daemon.debug radvd[9872]: vlan2 recvmsg len=288
Apr 19 23:37:02 R7000 daemon.debug radvd[9872]: vlan2 received a packet
Apr 19 23:37:02 R7000 daemon.warn radvd[9872]: vlan2 received icmpv6 RS/RA packet on an unknown interface with index 5
Apr 19 23:37:02 R7000 daemon.debug radvd[9872]: polling for 5.213 second(s), next iface is br0
Apr 19 23:37:07 R7000 daemon.debug radvd[9872]: timer_handler called for br0
From the tcpdump, if I understand correctly, comcast is advertising me 2601:244:4180:696e::/64 prefix, but ddwrt for some reason isn't taking it. I tried forcing it with custom Radvd config but no dice:
Joined: 01 Dec 2021 Posts: 289 Location: Maryland, United States
Posted: Wed Apr 20, 2022 21:19 Post subject:
Comcast is deploying vCMTS in some locations. Since Comcast switched to vCMTS in my area with the original Netgear firmware I lost IPv6 after an hour or two. Using DD-WRT with Comcast vCMTS so far I have (as stated in the thread I started) I have been unable to obtain IPv6. I hope you fine a solution I can try!
Got IPv6 back guys after 'ip6tables -F INPUT', problem seemed to be in ip6tables INPUT chain, I wonder why it's an issue now, my ip6tables rules are stock to my knowledge:
Code:
root@R7000:~# ip6tables -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all * * ::/0 ::/0 state RELATED,ESTABLISHED
86 11672 ACCEPT icmpv6 * * ::/0 ::/0
0 0 ACCEPT all * * fe80::/64 ::/0
0 0 ACCEPT all br0 * ::/0 ::/0
6 990 DROP all * * ::/0 ::/0
I wonder what was getting dropped there, and what kind of rule I need to add to allow it.
Seems that I was missing:
ip6tables -A INPUT -p udp --dport 546 -j ACCEPT
Fix (added this to startup Firewall Commands):
ip6tables -F
ip6tables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
ip6tables -A INPUT -p icmpv6 -j ACCEPT
ip6tables -A INPUT -s fe80::/64 -j ACCEPT
ip6tables -A INPUT -p udp --dport 546 -j ACCEPT
ip6tables -A INPUT -i lo -j ACCEPT
ip6tables -A INPUT -i br0 -j ACCEPT
ip6tables -A INPUT -j DROP
Joined: 01 Dec 2021 Posts: 289 Location: Maryland, United States
Posted: Thu Apr 21, 2022 15:33 Post subject:
I applied your settings and now I can get IPv6 on the WAN on my R6300 with Comcast. However I do not have IPv6 on the LAN. Did you modify anything to enable the LAN?
No, I would look into radvd if I was you. FYI I don't enable dhcp6s, dhcp6s is just a complementary service to radvd, radvd on its own gets everything done.
radvd sends IPv6 address advertisements to your local hosts/devices so they can automatically assign IPv6 addresses
Joined: 01 Dec 2021 Posts: 289 Location: Maryland, United States
Posted: Sat Apr 23, 2022 1:12 Post subject:
I already had it set up they way you suggested but I do not get a LAN IPv6. Does any else have any suggestions on how to obtain a LAN IPv6 since my computer does not recognize IPv6 from the router.
