странные ошибки в логах BIND

Добрый день. Что бы это могло означать?

FORMERR resolving '35.142.71.217.in-addr.arpa/PTR/IN': 217.70.106.5#53: 1 Time(s)
    FORMERR resolving '35.143.71.217.in-addr.arpa/PTR/IN': 217.70.106.5#53: 1 Time(s)
    FORMERR resolving '35.94.64.80.in-addr.arpa/PTR/IN': 217.70.106.5#53: 1 Time(s)
    FORMERR resolving '3a.overclockers.ru/A/IN': 217.70.106.5#53: 1 Time(s)
    FORMERR resolving '468.rbn.nsk.ru/A/IN': 217.70.106.5#53: 1 Time(s)
    FORMERR resolving '468.smi.ru/A/IN': 217.70.106.5#53: 1 Time(s)
    FORMERR resolving '5.142.71.217.in-addr.arpa/PTR/IN': 217.70.106.5#53: 1 Time(s)
    FORMERR resolving '66.254.3.72.in-addr.arpa/PTR/IN': 217.70.106.5#53: 1 Time(s)
    FORMERR resolving '71.143.71.217.in-addr.arpa/PTR/IN': 217.70.106.5#53: 1 Time(s)
    FORMERR resolving '81.143.71.217.in-addr.arpa/PTR/IN': 217.70.106.5#53: 1 Time(s)
    FORMERR resolving '96.142.71.217.in-addr.arpa/PTR/IN': 217.70.106.5#53: 1 Time(s)
    FORMERR resolving 'A.NIC.de/A/IN': 217.70.106.5#53: 1 Time(s)
    FORMERR resolving 'ARWENA.NASK.WAW.PL/A/IN': 217.70.106.5#53: 1 Time(s)

Появилось в логах не так давно.