dhcp server returns core dump when i define network with mask 8
Frank Leonhardt
frank2 at fjl.co.uk
Tue Jul 23 15:10:47 UTC 2013
On 23/07/2013 13:35, J.McKeown at ru.ac.za wrote:
> Quoting Frank Leonhardt <frank2 at fjl.co.uk>:
>
>>
>> There are two common ways of defining a subnet mask - one is a dotted
>> quad (e.g. 255.255.255.0) and the other is with a slash and the
>> number of low-order bits - e.g. 192.168.1.0/8. Eight bits here means
>> you get 2^8 addresses (i.e. 256). Don't use the first and last
>> address in the range - the first is "complicated" (the network
>> address) and the last is for broadcast packets. This doesn't always
>> hold true but you're unlikely to come across exceptions.
>
> This is the wrong way round. the number after the slash indicates the
> number of bits in the network address - the high-order bits.
>
>> So, when you say you want to define a "network with mask 8" I don't
>> really know what you mean from your example. Do you mean a /8?
>>
>> 192.168.1.0/8 = range 192.168.1.1 192.168.1.254 with a subnet mask
>> of 255.255.255.0 (0xFFFFFF00)
>
> Nope. 192.168.1.0/24 = 192.168.1.1-255 mask 255.255.255.0.
> 192.168.1.0/8 doesn't start where you think it does (and is arguably
> the wrong way to specify that network) because all but the first 8
> bits are masked out - it's 192.0.0.0 - 192.255.255.255.
Quite correct - for some reason I got that bit backwards when I'm using
it every day the right way around. It's ludicrously hot and humid in
London at the moment, lack of sleep caused thereby &c...
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