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IPv6 ping - "no route to host"

Posted: Mon Mar 18, 2013 2:47 pm
by Dragonn
Hello there,

I have one RB with IPv6 connectivity and /48 subnet free to use, so I decided to make ovpn to my home Mikrotik and distribute IPv6 at home.

But there is one issue which I am unable to solve and looks quite weird to me... I have bridge interface br0 over ether+wlan interfaces with assigned IPv6 address and enabled advertising. I connect to WiFi, get IPv6 address and default gw via Mikrotik's link local address (dunno why not global one, but nevermind).

The main issue is I cannot reach any IPv6 device from Mikrotik because if I tried to ping PC's address, i got "no route to host". Why it don't knows route to it's directly connected network? Can you please try to help me find any solution of this? I don't know where could be mistake, I think I configured everything correctly :(

I currently use RouterOS v. 5.22 on RB433 at home. Please see some configuration snippets below, I truncated them for better simplicity.

Linux:
$ ip -6 r
2001:1528:213:2::/64 dev wlan0  proto kernel  metric 256  expires 2591987sec mtu 1500 advmss 1440 hoplimit 4294967295
fe80::/64 dev wlan0  proto kernel  metric 256  mtu 1500 advmss 1440 hoplimit 4294967295
default via fe80::210:5aff:fe71:e9bb dev wlan0  proto kernel  metric 1024  expires 1787sec mtu 1500 advmss 1440 hoplimit 4294967295
Mikrotik:
[admin@Mikrotik] > ipv ad pr          
Flags: X - disabled, I - invalid, D - dynamic, G - global, L - link-local 
 #    ADDRESS                                     FROM-POOL INTERFACE                         ADVERTISE
 ...
 1  G 2001:1528:213:2::1/64                                 br0                               yes      
 ...
 3 DL fe80::210:5aff:fe71:e9bb/64                           br0                               no       
 ...

[admin@Mikrotik] > ipv r pr      
Flags: X - disabled, A - active, D - dynamic, C - connect, S - static, r - rip, o - ospf, b - bgp, 
U - unreachable 
 #      DST-ADDRESS              GATEWAY                  DISTANCE
 ...
 1 ADC  2001:1528:213:2::/64     br0                             0
 ...

[admin@Mikrotik] > ping 2001:1528:213:2::1
HOST                                     SIZE TTL TIME  STATUS                                         
2001:1528:213:2::1                         56  64 0ms   echo reply                                     
2001:1528:213:2::1                         56  64 0ms   echo reply                                     
2001:1528:213:2::1                         56  64 0ms   echo reply                                     
    sent=3 received=3 packet-loss=0% min-rtt=0ms avg-rtt=0ms max-rtt=0ms 

[admin@Mikrotik] > ping 2001:1528:213:2:216:eaff:fe5c:142e         
HOST                                     SIZE TTL TIME  STATUS                                         
                                                        no route to host                               
                                                        no route to host                               
                                                        no route to host                               
    sent=3 received=0 packet-loss=100% 
At the end ... I have found one solution how to make router working, but I don't like it. It's a little bit more weird then issue it self.
[admin@Mikotik] > ipv r add dst-address=2001:1528:213:2::/65 gateway=br0
[admin@Mikotik] > ipv r add dst-address=2001:1528:213:2:8000::/65 gateway=br0

[admin@Mikotik] > ipv r pr                                                   
Flags: X - disabled, A - active, D - dynamic, C - connect, S - static, r - rip, o - ospf, b - bgp, 
U - unreachable 
 #      DST-ADDRESS              GATEWAY                  DISTANCE
 ...
 1 ADC  2001:1528:213:2::/64     br0                             0
 2 A S  2001:1528:213:2::/65     br0                             1
 3 A S  2001:1528:213:2:8000:... br0                             1
 ...

[admin@Mikotik] > ping 2001:1528:213:2:216:eaff:fe5c:142e                    
HOST                                     SIZE TTL TIME  STATUS                                         
2001:1528:213:2:216:eaff:fe5c:142e         56  64 7ms   echo reply                                     
2001:1528:213:2:216:eaff:fe5c:142e         56  64 1ms   echo reply                                     
2001:1528:213:2:216:eaff:fe5c:142e         56  64 1ms   echo reply                                     
    sent=3 received=3 packet-loss=0% min-rtt=1ms avg-rtt=3ms max-rtt=7ms 
Thanks for your help! Dragonn

Re: IPv6 ping - "no route to host"

Posted: Thu Mar 21, 2013 4:43 pm
by Dragonn
any kind of idea from anyone? I am quite clueless at this stage ...

Re: IPv6 ping - "no route to host"

Posted: Sun Oct 13, 2013 2:06 pm
by oreggin
Same problem here. I wrote it to support for months ago, I asked they multiple times if this is a known bug or not but no answare comes back.

Re: IPv6 ping - "no route to host"

Posted: Sun Oct 13, 2013 2:15 pm
by oreggin
Reboot can resolve it temporarily but after a random time the router lost again their routes to own connected neigbours. It can only reach itself. Really very strange thing. It would be appreciated if someone from MT could tells something if they knows this issue and working on it or not.

Re: IPv6 ping - "no route to host"

Posted: Wed Oct 16, 2013 3:27 pm
by madprogrammer
Have a similar issue on my CCR. Addresses of the router:
Flags: X - disabled, I - invalid, D - dynamic, G - global, L - link-local 
 #    ADDRESS                                     FROM-POOL INTERFACE                                                              ADVERTISE
 0  G 2001:67c:xxxx::4e:1/63                                b1-bridge                                                       no       
 1  G 2001:67c:xxxx:300::10/64                             b2-bridge                                                            yes      
Routes:
Flags: X - disabled, A - active, D - dynamic, 
C - connect, S - static, r - rip, o - ospf, b - bgp, U - unreachable 
 #      DST-ADDRESS              GATEWAY                  DISTANCE
 0 A S  ::/0                     2001:67c:xxxx::3                1
 1 ADC  2001:67c:xxxx::/63       b1-bridge                0
 2 ADC  2001:67c:xxxx:300::/64   b2-bridge                     0
The router sometimes doesn't see its own connected neighbours. Sometimes if trying to ping a directly connected neighbour, it will send the packet to the default gateway (route #0), then the default gateway will send it back to the router, and then it will repeat until the TTL is expired. Sometimes, pinging any external IPv6 address (except directly connected neighbours or the default gateway) will show "Network is down" error. This behaviour is occuring pretty randomly to me. So far I managed to fix it just by disabling and then re-enabling the IPv6 local addresses and the IPv6 default route. Don't know, maybe it caused the RouterOS to do some magic inside and the inconsistent state of routing was somehow fixed. Until the next reboot....

Re: IPv6 ping - "no route to host"

Posted: Sat Oct 19, 2013 2:17 pm
by oreggin
Did you all mentioned it to MT support?

Re: IPv6 ping - "no route to host"

Posted: Sat Oct 19, 2013 4:57 pm
by Dragonn
Did you all mentioned it to MT support?
Not yet, I made it work with two routes hack and didn't do anything more with that.

Re: IPv6 ping - "no route to host"

Posted: Wed Oct 17, 2018 5:57 pm
by kramer
Did you all mentioned it to MT support?
Not yet, I made it work with two routes hack and didn't do anything more with that.
hi,how did you hack with 2 routes ????