Name

DNSE-742 — Nameserver response contains invalid flags

Severity

A (alert)

Message text

%s response from %s has %s bit %s

Description

The response from printed nameserver has incorrect flag setting. There are three possibilities:

  • The response flag (QR) is not set.

  • The truncation (TC) flag is set in the TCP response. The flag is used to inform client that required response cannot fit into UDP packet and should be re-request via TCP connection. In TCP, this flag has no sense and it may be an attempt to compromise client.

  • The reserved bits are not zero.

Whole answer is ignored and next server is tried.

See also

logging(7)

Authors

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