#17396: LAN clients unable to communicate via IPv6 while Internet connectivity
works
--------------------------+-----------------------------------
Reporter: mhoran | Owner: developers
Type: defect | Status: new
Priority: normal | Milestone:
Component: base system | Version: Barrier Breaker 14.07
Resolution: | Keywords:
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Comment (by mhoran):
Replying to [comment:1 cyrus]:
> OK, that sounds a bit strange. First of all, there is no difference as
to how ping6 and ssh do the neighbor lookup (in fact the kernel handles it
for both).
Ah, interesting. Perhaps it's just that the ping is more "persistent", in
that it tries to make a new connection every second. The first couple of
pings fail, then succeed, in the following way:
{{{
[mhoran@mhoran-x1-carbon] ~% ping6 challenger
PING challenger(2604:2000:1280:a089:82ee:73ff:fe12:71cf) 56 data bytes
From 2604:2000:1280:a089::1 icmp_seq=1 Destination unreachable: Port
unreachable
64 bytes from 2604:2000:1280:a089:82ee:73ff:fe12:71cf: icmp_seq=3 ttl=64
time=1.53 ms
}}}
SSH typically fails to connect immediately on the first try, if I force
IPv6 (or use the address directly).
{{{
[mhoran@mhoran-x1-carbon] ~% ssh -vvv -6 challenger
OpenSSH_6.6.1, OpenSSL 1.0.1i-dev xx XXX xxxx
debug1: Reading configuration data /home/mhoran/.ssh/config
debug1: /home/mhoran/.ssh/config line 3: Applying options for challenger
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to challenger [2604:2000:1280:a089:82ee:73ff:fe12:71cf]
port 22.
debug1: connect to address 2604:2000:1280:a089:82ee:73ff:fe12:71cf port
22: Connection refused
ssh: connect to host challenger port 22: Connection refused
}}}
Subsequent tries will typically hang, then time out.
{{{
[mhoran@mhoran-x1-carbon] ~% ssh -vvv
2604:2000:1280:a089:82ee:73ff:fe12:71cf
OpenSSH_6.6.1, OpenSSL 1.0.1i-dev xx XXX xxxx
debug1: Reading configuration data /home/mhoran/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 2604:2000:1280:a089:82ee:73ff:fe12:71cf
[2604:2000:1280:a089:82ee:73ff:fe12:71cf] port 22.
debug1: connect to address 2604:2000:1280:a089:82ee:73ff:fe12:71cf port
22: Connection timed out
ssh: connect to host 2604:2000:1280:a089:82ee:73ff:fe12:71cf port 22:
Connection timed out
}}}
> You mentioned fallback to IPv4 so I assume you are using some kind of
DNS inside your home for the ssh. Since you have disabled ra_management
IPv6 addresses aren't learnt through DHCPv6 so it's probably the manual
stuff for "challenger" you added to dhcp?
I'm using dnsmasq to provide a fallback A record, in addition to an AAAA
record. I've configured this via /etc/config/dhcp.
I disabled ra_management as I discovered a bug in NetworkManager which
would result in only the ULA subnet being configured on hosts. Seeing as
auto configuration worked fine, I disabled ra_management so that only the
auto-assigned addresses would be on my system.
> Do you do the ping6 with the same hostname or using the IPv6 address to
make it work again?
Hostname.
> Does it make a difference if you try to SSH to the IPv6 address instead
of the hostname?
No.
> Usually inter-device connectivity shouldn't be a concern of the router
especially since you have a bridged lan-interface, however there is some
multicast management involved in the bridge-layer.
>
> Could you try to add:
> option igmp_snooping 0
>
> into the config interface lan section of /etc/config/network and do a
reboot afterwards and see if it makes any difference?
I see the same bug after adding igmp_snooping to /etc/config/network.
--
Ticket URL: <https://dev.openwrt.org/ticket/17396#comment:3>
OpenWrt <http://openwrt.org>
Opensource Wireless Router Technology
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