Host not reachable over UDP

[Petr Man]

Hi guys,

I have now done the obvious - swapped out the kernel. Upgrading to 4.5.7
fixed the problem!

udp    UNCONN     0      1408      *:655                   *:*
      users:(("tincd",pid=3242,fd=7))
tcp    LISTEN     0      3         *:655                   *:*
      users:(("tincd",pid=3242,fd=6))

Thank you very much for your time.

Petr

On Fri, Jul 15, 2016 at 7:22 AM, Petr Man <petr at madnetwork.org> wrote:

> Hi Etienne,
>
> I tried the patch, no change at all. Attached is a new log and also strace
> log. There is a FD 7 opened (the UDP socket), used and yet "ss -nlptu"
> doesn't see it.
>
> I have a suspicion now there is something wrong with the distro/kernel. As
> a test:
>
> netcat -ul -p600
> ss -nlptu | grep netcat
>
> gives me no output...
>
> Petr
>
> On Thu, Jul 14, 2016 at 8:27 PM, Etienne Dechamps <etienne at edechamps.fr>
> wrote:
>
>> You might want to try with https://github.com/gsliepen/tinc/pull/120 -
>> that said, this bug probably doesn't explain everything because tinc is
>> supposed to log a message from setup_vpn_in_socket() anyway, but there's no
>> such message in your log. In addition, I really don't see any way the
>> "Received UDP packet from unknown source" message could be logged if the
>> UDP socket isn't functional.
>>
>>
>> On 14 July 2016 at 05:10, Petr Man <petr at madnetwork.org> wrote:
>>
>>> Good morning,
>>>
>>> Here is the log, I don't see anything unusual. I took the same tinc
>>> binary and tried on two other machines and it works fine - binds to 655/UDP
>>> without issues:
>>> udp    UNCONN     0      0                      *:655
>>> *:*      users:(("tincd",18872,7))
>>> tcp    LISTEN     0      3                      *:655
>>> *:*      users:(("tincd",18872,6))
>>>
>>>
>>> Petr
>>>
>>> On Thu, Jul 14, 2016 at 12:18 AM, Rob Townley <rob.townley at gmail.com>
>>> wrote:
>>>
>>>> Have anything to do with firewall locations, meaning home vs work vs
>>>> public vs lockdown.  Probably not it at all.
>>>> On Jul 13, 2016 3:22 PM, "Etienne Dechamps" <etienne at edechamps.fr>
>>>> wrote:
>>>>
>>>>> That's strange. Can you post a detailed log from the affected node
>>>>> (run tincd -d5 -D), especially the initialization phase?
>>>>>
>>>>> On 13 July 2016 at 16:17, Petr Man <petr at madnetwork.org> wrote:
>>>>>
>>>>>> Dear all,
>>>>>>
>>>>>> I have been successfully running for quite some time a tinc 1.1
>>>>>> network in switch mode. I recently added a new node, that refuses to
>>>>>> communicate over UDP.
>>>>>> Running "tinc info mynode" from a different box returns:
>>>>>> Reachability: directly with TCP
>>>>>>
>>>>>> It appears that tincd is not listening on UDP port 655 on "mynode".
>>>>>> Running "ss -nlptu | grep tincd":
>>>>>> tcp    LISTEN     0      3         *:655                   *:*
>>>>>>             users:(("tincd",pid=10097,fd=6))
>>>>>>
>>>>>> In the log there is a large number of these messages:
>>>>>> Received UDP packet from unknown source 123.321.123.321 port 655
>>>>>>
>>>>>> I am puzzled how is tincd getting the packets if it is not listening
>>>>>> on 655/UDP.
>>>>>>
>>>>>> When I start netcat on the node on port 655/UDP I can see garbage
>>>>>> coming in from the other nodes trying to initiate an UDP connection.
>>>>>>
>>>>>> Would you have any hints where to start debugging this? All machines
>>>>>> are configured the same way and work fine (various linux versions,
>>>>>> windows). This particular box is on Ubuntu Xenial kernel 4.3.5.
>>>>>>
>>>>>> Best,
>>>>>> Petr
>>>>>>
>>>>>> _______________________________________________
>>>>>> tinc mailing list
>>>>>> tinc at tinc-vpn.org
>>>>>> https://www.tinc-vpn.org/cgi-bin/mailman/listinfo/tinc
>>>>>>
>>>>>>
>>>>>
>>>>> _______________________________________________
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>>>>>
>>>>>
>>>
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>>
>
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