Netmask issue
Reissom Beshir
Reissom_Beshir at Mitel.com
Fri Oct 2 22:52:55 UTC 2009
Simon Hobson wrote:
>>So does this bug exist in dhcp-4.0?
>
> Is it a bug ? The OP didn't specify a netmask option to send to clients.
> You could argue that the logic is wrong in how the value is chosen, but if
> the admin specifies the right value then it works just fine.
>
If I am not mistaken the expected behaviour is for dhcpd to take the netmask
set in the subnet statement and place that in the netmask option when the
option is not explicitly specified. In this case the OP did specify the
right value in the subnet decl, but dhcpd chose its own value. This is
incorrect. Does that not make it a bug?
And according to the documentation...
man dhcpd.conf:
The subnet statement
...
Although a netmask must be given with every subnet declaration,
it is recommended that if there is any variance in subnet masks
at a site, a subnet-mask option statement be used in each subnet
declaration to set the desired subnet mask, since any subnet-mask
option statement will override the subnet mask declared in the
subnet statement.
man dhcp-options:
option subnet-mask ip-address;
The subnet mask option specifies the client's subnet mask as
per RFC 950. If no subnet mask option is provided anywhere in
scope, as a last resort dhcpd will use the subnet mask from the
subnet declaration for the network on which an address is
being assigned. However, any subnet-mask option declaration that
is in scope for the address being assigned will override the
subnet mask specified in the subnet declaration.
Thanks,
Reissom
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