[Dnsmasq-discuss] How small is a 'small network'?

[Norman Gray]

Simon and Jonathan, hello.

On 17 Nov 2015, at 17:44, Simon Kelley wrote:

> On 16/11/15 22:05, Norman Gray wrote:
>>
>> Greetings.
>>
>> The dnsmasq documentation stresses that it's a good solution for
>> 'small networks', but how small is small?  The overview seems to
>> give as examples home networks, or mentions dnsmasq running in a
>> router (implicitly a SOHO router).

Many thanks to you both for both the reassurance and the advice.

> DHCP is slighly more complex: dnsmasq maintains the DHCP lease
> database in memory, and every time it changes (lease added, lease
> expires, lease removed) then the whole lot gets written out to a file
> for persistence. With good hardware and fast disks, that's no problem
> at all. With a little router using flash or a USB drive, it might be.
> The rate of writing, long term, depends on lease length as well. If
> you're using day or week long leases, no problem. If you have huge
> turnover of clients and a shortage of IP addresses and have to use
> short leases, then the load will be greater.

The majority of the assignments will be static, so long leases, and the 
machines on these networks will be essentially office machines, so 
without major correlation in switch-on times.

We're using private networks and plan to experiment with IPv6, so we're 
not too short of addresses.

>> The manpage mentions that 'Dnsmasq is capable of handling DNS and
>> DHCP for at least a thousand clients.'  That's about the number of
>> clients I'm thinking of, so that's good, but is there a 'with ease'
>> elided there, or a 'without overwhelming pain'?  Would I, in short,
>> be storing up trouble for myself?
>>
>
>
> On a decent server, you'll be fine.

Excellent.

> One last thing to consider. Dnsmasq doesn't do DHCP failover, so if
> you think you really need high availability, you should look a
> dhcpcd/BIND.

I don't _think_ we'll need that, but I'll keep the advice in mind.

Thanks again.  Best wishes,

Norman


-- 
Norman Gray  :  https://nxg.me.uk
SUPA School of Physics and Astronomy, University of Glasgow, UK