[atlas] Effect of "Resolve on Probe"-option

On 2017/12/03 17:36 , Stephane Bortzmeyer wrote:
> Atlas rejects 'use_probe_resolver': False if you did not specify a
> target:
> 
> Status 400, reason "{"error":{"status":400,"errors":[{"source":{"pointer":"/definitions/0"},"detail":"`target` cannot be null if `use_probe_resolver` is not specified"}],"code":102,"detail":"There was a problem with your request","title":"Bad Request"}}"
> 
> 'resolve_on_probe' seems ignored.
> 

> 2) Use an external server (here, Quad9, option -e):
> 
> % atlas-resolve -r 5 -v -e 9.9.9.9 thepiratebay.org 
> {'definitions': [{'protocol': 'UDP', 'description': 'DNS resolution of thepiratebay.org via nameserver 9.9.9.9', 'af': 4, 'query_argument': 'thepiratebay.org', 'query_type': 'A', 'query_class': 'IN', 'target': '9.9.9.9', 'set_rd_bit': True, 'type': 'dns', 'use_probe_resolver': False}], 'is_oneoff': True, 'probes': [{'requested': 5, 'type': 'area', 'value': 'WW', 'tags': {'include': ['system-ipv4-works']}}]}
> Measurement #10397471 for thepiratebay.org/A uses 5 probes
> Nameserver 9.9.9.9
> [104.27.216.28 104.27.217.28] : 5 occurrences 
> Test #10397471 done at 2017-12-03T16:19:41Z

It may be worth pointing out that resolve_on_probe has effect if two
conditions are met:
1) use_probe_resolver is false
2) the measurement target is a dns name (as opposed to an IP address
literal)

In your quad-9 example, the target is a literal, so resolve_on_probe has
no effect.

The following DNS measurement uses resolve_on_probe:
https://atlas.ripe.net/measurements/10404214/

Here is an example measurement result:
{"af":4,"dst_addr":"193.0.9.7","from":"73.34.225.118","fw":4780,"group_id":10404214,"lts":38,"msm_id":10404214,"msm_name":"Tdig","name":"manus.authdns.ripe.net","prb_id":21675,"proto":"UDP","result":{"ANCOUNT":1,"ARCOUNT":0,"ID":55944,"NSCOUNT":0,"QDCOUNT":1,"abuf":"2oiEAAABAAEAAAAAA3d3dwRyaXBlA25ldAAAAQABwAwAAQABAABUYAAEwQAGiw==","rt":131.954,"size":46},"src_addr":"192.168.29.154","stored_timestamp":1512385062,"timestamp":1512385044,"type":"dns"}

The probe reports that it resolved 'name' manus.authdns.ripe.net to
'dst_addr' 193.0.9.7

Philip