Host not reachable over UDP

[Petr Man]

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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