[DHCPDISCOVER]unknown network segment.

[Glenn Satchell]

Hi Eugene

The 'via' part of the log message indicates these two IPs are acting as
DHCP relay agents. My guess is that they are two routers with vrrp (or
other virtual address) advertising x.x.x.161 as the gateway.

What this means is that there is a subnet somewhere on the *other* side pf
these routers that is where the client is. It is this other subnet that is
not defined so the dhcp server doesn't know how to assign an address. You
can check this by using tcpdump to look at the packets - it will have a
field with the address of the gateway on that subnet.

regards,
-glenn

On Thu, October 16, 2014 8:20 pm, Eugène Ngontang wrote:
> Yes Simon exactly. But as you the subnet is declared. That's why I'm then
> confused, and want to know what other reason can cause this. I have not
> seen any real document about this issue.
> Thanks.
> Le 16 oct. 2014 11:10, "Simon Hobson" <dhcp1 at thehobsons.co.uk> a écrit :
>
>> Eugène Ngontang <sympavali at gmail.com> wrote:
>>
>> > range      X.X.X.162 X.X.X.190;
>>
>> No.
>> You have devices at .162 and .163, see the "via ..." bit here :
>>
>> > > Oct 12 04:02:27 SERVERHOSTNAME dhcpd: DHCPDISCOVER from
>> 00:aa:aa:aa:aa:aa via X.X.X.163: unknown network segment
>> > > Oct 12 04:02:27 SERVERHOSTNAME dhcpd: DHCPDISCOVER from
>> 00:aa:aa:aa:aa:aa  via X.X.X.162: unknown network segment
>>
>> These addresses are also in the range you have specified so the server
>> can
>> attempt to give them to other clients. This is "a bad thing". So as a
>> minimum you need to change your range statement to "X.X.X.164 X.X.X.190"
>> -
>> and if you have any other devices with addresses in that range then they
>> need excluding too.
>>
>> However, that still doesn't address your main problem. "unknown network
>> segment" normally means that there is no subnet declaration which
>> includes
>> the IP address of the relay agent.
>>
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