Hi all, it appears that some probes never return NSID, when requested, while others do, for the same query. For example: https://atlas.ripe.net/measurements/1875836/#!general As you can see NSID is set to True. These are the raw results from the two probes, for a one-off DNS UDM: results = { u'6012': [{u'lts': 230, u'proto': u'UDP', u'from': u'193.0.19.108', u'msm_id': 1875836, u'af': 4, u'timestamp': 1424384037, u'fw': 4670, u'msm_name': u'Tdig', u'prb_id': 6012, u'result': {u'abuf': u'OQGEAAABAAEAAAABA29yZwAABgABwAwABgABAAADhAAzAmEwA29yZwthZmlsaWFzLW5zdARpbmZvAANub2PAKHfjQ2sAAAcIAAADhAAJOoAAAVGAAAApEAAAAAAAACUAAwAhbnMwMDBiLmFwcDcubnJ0MS5hZmlsaWFzLW5zdC5pbmZv', u'rt': 312.971, u'NSCOUNT': 0, u'QDCOUNT': 1, u'answers': [{u'RNAME': u'noc.afilias-nst.info.', u'NAME': u'org.', u'MNAME': u'a0.org.afilias-nst.info.', u'TTL': 900, u'SERIAL': 2011382635, u'TYPE': u'SOA'}], u'ID': 14593, u'ARCOUNT': 1, u'ANCOUNT': 1, u'size': 132}, u'src_addr': u'193.0.19.108', u'group_id': 1875836, u'type': u'dns', u'dst_addr': u'199.19.56.1'}], u'10039': [{u'lts': 166, u'proto': u'UDP', u'from': u'96.237.232.254', u'msm_id': 1875836, u'af': 4, u'timestamp': 1424384040, u'fw': 4670, u'msm_name': u'Tdig', u'prb_id': 10039, u'result': {u'abuf': u'qxGAgAABAAEAAAABA29yZwAABgABwAwABgABAAAB3QAzAmEwA29yZwthZmlsaWFzLW5zdARpbmZvAANub2PAKHfjQ2UAAAcIAAADhAAJOoAAAVGAAAApD6AAAAAAAAA=', u'rt': 8.299, u'NSCOUNT': 0, u'QDCOUNT': 1, u'answers': [{u'RNAME': u'noc.afilias-nst.info.', u'NAME': u'org.', u'MNAME': u'a0.org.afilias-nst.info.', u'TTL': 477, u'SERIAL': 2011382629, u'TYPE': u'SOA'}], u'ID': 43793, u'ARCOUNT': 1, u'ANCOUNT': 1, u'size': 95}, u'src_addr': u'192.168.13.40', u'group_id': 1875836, u'type': u'dns', u'dst_addr': u'199.19.56.1'}] } Sagan tells me, for probe 6012, responses[0].abuf.raw_data is: {'HEADER': {'AA': True, 'QR': True, 'AD': False, 'NSCOUNT': 0, 'QDCOUNT': 1, 'ANCOUNT': 1, 'TC': False, 'RD': False, 'ARCOUNT': 1, 'CD': False, 'ReturnCode': 'NOERROR', 'OpCode': 'QUERY', 'RA': False, 'Z': 0, 'ID': 14593}, 'AnswerSection': [{'Retry': 900, 'Name': u'org.', 'NegativeTtl': 86400, 'Refresh': 1800, 'MasterServerName': u'a0.org.afilias-nst.info.', 'Expire': 604800, 'MaintainerName': u'noc.afilias-nst.info.', 'TTL': 900, 'Serial': 2011382635, 'Type': 'SOA', 'Class': 'IN', 'RDlength': 51}], 'QuestionSection': [{'Qclass': 'IN', 'Qtype': 'SOA', 'Qname': u'org.'}], 'EDNS0': {'ExtendedReturnCode': 0, 'Option': [{'OptionCode': 3, 'OptionName': 'NSID', 'NSID': u'ns000b.app7.nrt1.afilias-nst.info', 'OptionLength': 33}], 'UDPsize': 4096, 'Version': 0, 'Z': 0, 'Type': 'OPT', 'Name': u'.'}} NSID is present. And for 10039: {'HEADER': {'AA': False, 'QR': True, 'AD': False, 'NSCOUNT': 0, 'QDCOUNT': 1, 'ANCOUNT': 1, 'TC': False, 'RD': False, 'ARCOUNT': 1, 'CD': False, 'ReturnCode': 'NOERROR', 'OpCode': 'QUERY', 'RA': True, 'Z': 0, 'ID': 43793}, 'AnswerSection': [{'Retry': 900, 'Name': u'org.', 'NegativeTtl': 86400, 'Refresh': 1800, 'MasterServerName': u'a0.org.afilias-nst.info.', 'Expire': 604800, 'MaintainerName': u'noc.afilias-nst.info.', 'TTL': 477, 'Serial': 2011382629, 'Type': 'SOA', 'Class': 'IN', 'RDlength': 51}], 'QuestionSection': [{'Qclass': 'IN', 'Qtype': 'SOA', 'Qname': u'org.'}], 'EDNS0': {'ExtendedReturnCode': 0, 'Option': [], 'UDPsize': 4000, 'Version': 0, 'Z': 0, 'Type': 'OPT', 'Name': u'.'}} NSID is missing. Why is this? I've tried increasing the payload size, this makes no difference. I get the same when I try for SOA . @ k.root-servers.net: Compare these outcomes: https://atlas.ripe.net/measurements/1875933/ https://atlas.ripe.net/measurements/1875926/ It appears to me that probe 10039 (or its network) has a problem of sorts, causing this. It would be great if faulty probes can be weeded out, if this is really the case. BTW, I am always getting "null" on the NSID field in the web interface, regardless of whether it lives in abuf, or not. This seems to be a bug. ~paul