how define network with mask 8 for dhcp server?

[Andreas Nilsson]

On Tue, Aug 6, 2013 at 11:29 AM, s m <sam.gh1986 at gmail.com> wrote:

> thanks Andreas, that's it!!!
> you know i have user interface program for dhcp. users don't know how dhcp
> works and just enter desired range in text box. i should handle all entered
> ranges. in order to do that, i should know how dhcp works with all
> different ranges and return errors if some ranges is not equivalent like
> the sample one.
>

Ok. Someone more versed in debugging should probably determine if the crash
is in libc or just that dhcp does not handle malloc error.


>
> so. if i want to have network with mask 8, i should limit my range, right?
> have you any suggestion what is the maximum range for netmask 8?
> thanks for your reply again. it clears my mind:)
>

Exactly.

I just tried
192.0.0.1-192.220.255.255 which works ( takes ~3 minutes to start, using
4.5gb of ram )
and then
192.0.0.1-192.221.255.255 which segfaults.

The machine I test on does have 16gb of ram and 16gb of swap, so there
should be a lot more mem available.

Best regards
Andreas

>
>
> On Tue, Aug 6, 2013 at 1:35 PM, Andreas Nilsson <andrnils at gmail.com>wrote:
>
>>
>>
>>
>> On Tue, Aug 6, 2013 at 10:59 AM, Andreas Nilsson <andrnils at gmail.com>wrote:
>>
>>>
>>>
>>>
>>> On Tue, Aug 6, 2013 at 10:40 AM, Olivier Nicole <
>>> olivier.nicole at cs.ait.ac.th> wrote:
>>>
>>>> Sam,
>>>>
>>>> > my problem is to know how define a network with mask 8 and dhcp server
>>>> > works correctly with it! you know if i config my dhcpd.conf like
>>>> below, i
>>>> > have core dump either:
>>>> > subnet 10.0.0.0 netmask 255.0.0.0
>>>> > {
>>>> >     range 10.0.0.1 10.255.255.254;
>>>> > }
>>>> >
>>>> > do you know how should i define my range ??
>>>>
>>>> The reason may be that 2^24 machines in a subnet is such a non-sense
>>>> that dhcp simply cannot manage it.
>>>>
>>>> Best regards,
>>>>
>>>> Olivier
>>>>
>>>> >
>>>> > On Tue, Aug 6, 2013 at 12:23 PM, Olivier Nicole <
>>>> Olivier.Nicole at cs.ait.ac.th
>>>> >> wrote:
>>>> >
>>>> >> Sam,
>>>> >>
>>>> >> > subnet 192.0.0.0 netmask 255.0.0.0
>>>> >>
>>>> >> I know it is not the answer to your question, but you are wrong in
>>>> your
>>>> >> guess that 192.0.0.0/8 is all private IPs. Only 192.168.0.0/16 is.
>>>> >>
>>>> >> I know that for certain because my own IP starts with 192.
>>>> >>
>>>> >> If you want a full /8 private, you can only use 10.0.0.0/8
>>>> >>
>>>> >> Bets regards,
>>>> >>
>>>> >> Olivier
>>>> >>
>>>> >> --
>>>> >>
>>>>
>>>>
>>> Well, I would guess it may run out of memory... I did a few tests:
>>> 192.0.0.0 - 192.128.255.255 does work ( using ~2.5Gb  RAM ).
>>> 192.0.0.0 - 192.192.255.255 does work ( using ~4Gb RAM ).
>>> 192.0.0.0 - 192.200.255.255 does work ( using ~4.2Gb RAM ).
>>> 192.0.0.0 - 192.224.255.255 dumps core
>>>
>>> Why would you want to have such a huge range?
>>>
>>> Best regards
>>> Andreas
>>>
>>
>> Also, a quick look at the core file gives same indications:
>> #0  0x0000000800c67a21 in _malloc_prefork () from /lib/libc.so.7
>> #1  0x0000000800c6b72a in malloc () from /lib/libc.so.7
>> #2  0x000000000047b43b in omapi_object_dereference ()
>> #3  0x00000000004844db in do_ip4_hash ()
>> #4  0x0000000000484571 in do_ip4_hash ()
>> #5  0x0000000000438a45 in pool_timer ()
>> #6  0x000000000041dcd7 in trace_conf_stop ()
>> #7  0x000000000041fc4e in trace_conf_stop ()
>> #8  0x0000000000420698 in trace_conf_stop ()
>> #9  0x0000000000420ecc in trace_conf_stop ()
>> #10 0x0000000000420197 in trace_conf_stop ()
>> #11 0x00000000004247f3 in trace_conf_stop ()
>> #12 0x000000000041f210 in trace_conf_stop ()
>> #13 0x000000000040f3bf in lease_pinged ()
>> #14 0x000000000040d451 in ?? ()
>> #15 0x00000008007d7000 in ?? ()
>> #16 0x0000000000000000 in ?? ()
>>
>> Best regards
>> Andreas
>>
>>
>