Re: [PATCH] dns_multicast_local configuration option

On 1/08/2013 3:35 a.m., Alex Rousskov wrote:
> On 07/31/2013 09:02 AM, Amos Jeffries wrote:
>
>> Wider testing in production (by Ralf Hildenbrandt) has identified that
>> the mDNS support added in 3.4 can produce a large number amount of
>> multicast traffic from .arpa lookups even if mDNS is not setup on the
>> local network.
> Should not mDNS be turned off by default then? Setups that need it can
> always explicitly enable it, right?
>
>
>> It would be nice to implement a fast mechanism for determining whether
>> the PTR lookups are for LAN or WAN addresses
>> to decide better whether to send the query as mDNS.
> If the additional traffic volume is significant, perhaps the option
> should be turned off by default even if Squid knows that mDNS is setup
> on the network and the PTR lookup is for the right class of addresses.
>
>> + This enables local servers and devices to be contacted in an
>> + ad-hoc or zero-configuration network environment.
> Admins deploying to those environments can explicitly enable that
> option, of course.
>
>
> I know little about mDNS so I cannot have a strong opinion on this, but
> I am not looking forward to recommending that folks disable that option
> (unless they actually need it) because it may create too much traffic.

No more traffic than if they had one resolver which did not respond. And
only to the case of rDNS lookups.

Ralf's configuration has dst ACL rules or access.log IP fields which
caused the existing rDNS lookups to increase when those lookups had to
go to 2 resolvers
Technically the existing behavour is perfectly working in the current
release. It is just annoying and yes the default can be switched to off.

Amos
Received on Thu Aug 01 2013 - 07:18:52 MDT