[atlas] EDNS Client Subnet

On 2019/01/28 14:33 , Rami Al-Dalky wrote:
> When I tried to create a DNS measurement, I found that the only way to
> send DNS query with option is to set default_client_subnet to True.
> However, by setting this option, a DNS query will be sent with 0.0.0.0/0
> <http://0.0.0.0/0> as client subnet. 
> 
> Is there a reason why ECS is implemented that way? If it for privacy
> issue, the RFC recommends to sent the client IP with /24 prefix for IPv4
> and /56 for IPv6 to preserve the privacy.

Let me point out that we chose 0.0.0.0/0 to avoid all privacy issues.
The recommendation just reduces privacy issues.

At the same time, it was not clear to us what additional benefit it
would bring to RIPE Atlas measurements to include longer prefixes. In
particular, we assumed that the main purpose of this option would be to
measure interference by firewalls or other middle boxes.

Philip