Linux DHCP sending wrong parameters in offer packet

[Glenn Satchell]

Hi Yogesh,

Without seeing hyour config file I can guess that the option 43 setting
should be set in the global configuration rather than inside one of your
subnets. Setting it inside the subnet causes inheritance of those subnet
values.

To confirm, could you please post your dhcpd.conf? If it is is very large
perhaps you might post the relevant parts.

regards,
-glenn
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On Fri, January 25, 2019 11:41 pm, Gaikwad Yogesh wrote:
> Hi,
>
>
> There is issue that linux DHCP is sending wrong parameters while sending
> offer packet for Cisco AP's in one of our office locations.
>
> I have taken packet captures on the DHCP server side.
>
>
> As you can see in below packet capture there is DHCP DISCOVER message
> from Cisco AP requesting for IP and other parameters.
>
> Then in DHCP offer packet, it offers IP from correct subnet, but with
> wrong router IP, subnet mask and broadcast address.
>
> Basically, my observation is that it is giving wrong parameters in offer
> from the topmost subnet (as linux works from top to bottom approach) that
> has cisco option 43 configured. If I remove the Cisco option 43 from that
> subnet then it provides parameters from next subnet which has the Cisco
> option 43 in it.
>
> The correct subnet from which I am expecting that the AP should get all
> its parameters is configured at the end of the DHCP conf file.
>
>
> DHCP DISCOVER PACKET
>
>
> [cid:image001.png at 01D4B4D9.6F320900]
>
>
>
> DHCP OFFER PACKET
>
>
> [cid:image002.png at 01D4B4D9.6F320900]
>
>
>
>
>
> Best regards,
>
>
> Yogesh Gaikwad, Technical Architect - TECA Network
>
>
> Tieto Corporation, TSM
>
>
> email Yogesh.Gaikwad at tieto.com<mailto:Yogesh.Gaikwad at tieto.com>, direct
> +91 (0)2067303120
> Wing 1, Cluster D, EON Free Zone, MIDC Kharadi Knowledge Park, Pune - 411
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>
>
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>
>
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