[collectd] Server does not receive client data (network between both looks OK).

[Mariusz Gronczewski]

2011/10/14 Bruno Costacurta <techie at costacurta.org>:
>
> [snip]
>
>> Both server and client shows no firewall :
>>
>> ###### server
>> iptables -L
>> Chain INPUT (policy ACCEPT)
>> target     prot opt source               destination
>> Chain FORWARD (policy ACCEPT)
>> target     prot opt source               destination
>> Chain OUTPUT (policy ACCEPT)
>> target     prot opt source               destination
>>
>> ##### client
>> /sbin/iptables -L
>> Chain INPUT (policy ACCEPT)
>> target     prot opt source               destination
>> Chain FORWARD (policy ACCEPT)
>> target     prot opt source               destination
>> Chain OUTPUT (policy ACCEPT)
>> target     prot opt source               destination
>>
>> Same on the router.
>>
>
> As suggested in previous email the telnet use TCP, but collect UDP.
> So using netcat tools I tried to sent UDP and TCP to the server collectd
> from the client :
>
> nc  -w 5 X.X.X.X 22061      -> TCP reaches the server
> nc  -u -w 5 X.X.X.X 22061   -> UDP do NOT reaches the server
>
> So apparently it is a network problem.
> The TCP protocol reach the collectd server, but the UDP cannot reach the
> server.
>
> But there is no firewall on server neither client.
> So why this different behavior ?

try connecting them 'directly' or thru VPN/tunnel and then try it. If
it works it means your router (another linux box or some dedicated
hardware? ) is doing something funny :)
alternatively tunnel UDP thru TCP with something like socat