[Kea-users] pefdhcp help

[Nicolas Javier Pantazis]

Hello Francis, good evening. Any news on my question??
​*​*
*Old*
*​* *​*
*issue:*

   1. I suppose it sends unicast
   ​ ​
   and I know it does NOT work: [root at geek njp]# /opt/kea/sbin/perfdhcp -6
   -e address-only 2001:db8:beef:55:2
   2. I suppose it sends multicast
   ​ ​
   and works:  [root at geek njp]# /opt/kea/sbin/perfdhcp -6 -l eth0


Continuing with my thesis I came across a curious
​ ​
observation. Evaluating the
​ ​
physical
​ ​
resources of the server during a stress test using perfdhcp I noticed that
kea-dhcp6 does not use any memory, but a lot of processing power
​ ​
(ran pidstat server side twice)!! Can this be ?? What is the explanation
for this behavior??

Thank you so much for all the help


On Mon, Sep 11, 2017 at 12:07 PM, Nicolas Javier Pantazis <
nicolasjavierp at gmail.com> wrote:
>
> Hello Francis, good morning. I have resolved the issue, scouring through
the logs I found a legend that read something like "Kea dropped package
because it is Unicast" so I investigated the options of perfdhcp and
reformulated how I call the script.
>
> Before: [root at geek njp]# /opt/kea/sbin/perfdhcp -6 -e address-only
2001:db8:beef:55:2
> After:  [root at geek njp]# /opt/kea/sbin/perfdhcp -6 -l eth0
>
> It works now but I still do not completely understand why the client was
sending  packages on unicast to the server and not responding.
>
> Thank you for everything
>
>
> On Fri, Sep 8, 2017 at 11:21 AM, Francis Dupont <fdupont at isc.org> wrote:
>>
>> Nicolas Javier Pantazis writes:
>> > Hello Francis, good morning. Thank you for the reply, they do match
here is
>> > the output of the dhcpdump:
>> >
>> > 19:11:48.300621 IP6 2001:db8:beef:55::3.dhcpv6-client >
>> > 2001:db8:beef:55::2.dhcpv6-server: dhcp6 solicit
>>
>> => and lsof? Kea won't listen on 2001:db8:beef:55::2 by default.
>>
>> > The issue is very strange that is why I need your help. The strange
thing
>> > is that perfdhcp worked perfectly for ipv4.
>>
>> => DHCPv4 uses (by default, you can change the service socket type)
>> a BPF/LPF/etc socket, DHCPv6 uses standard UDP.
>>
>> Regards
>>
>> Francis Dupont <fdupont at isc.org>
>>
>> > > Can you check solicits are sent to an address the server is listen
to?
>> > > (you should have the destination address in your dump, for the server
>> > > lsof displays open file (including socket) details).
>> > > If not match, you should modify the perfdhcp argument or the Kea
server
>> > > config (cf interface configuration in DHCPv4 server guide).
>>
>> PS: you can have a kernel filter (ip6tables on Linux) which drops
>> incoming packets. Usually tcpdump/wireshark/etc can see them but
>> they are not delivered to the server.
>
>
>
>
> --
> Nicolas Javier Pantazis
>
> ---------- __o
> -------- _`\<,_      "The bike wants to go fast!   and brakes are death!"
> ------- (*)/ (*)
> ~~~~~~~~~~~~~~~~
>
>



--
Nicolas Javier Pantazis

---------- __o
-------- _`\<,_      "The bike wants to go fast!   and brakes are death!"
------- (*)/ (*)
~~~~~~~~~~~~~~~~
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