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Skip byte-based UDP classifiers on UDP/53 to avoid DNS false-matches#3932

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awick merged 1 commit into
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udp-skip-dns-port
Apr 30, 2026
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Skip byte-based UDP classifiers on UDP/53 to avoid DNS false-matches#3932
awick merged 1 commit into
mainfrom
udp-skip-dns-port

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@awick awick commented Apr 30, 2026

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  • parsers.c: in arkime_parsers_classify_udp, skip the byte-based classifier dispatch (Udp0/Udp1/Udp2) when either side of the session is on UDP/53. Port-based classifiers still run, so dns.c is unaffected. Parsers that legitimately need to run on UDP/53 should register a port-based classifier.
  • arkime.h: mark ARKIME_RETURN_IF_DNS_PORT as deprecated; keep the macro for out-of-tree parser compatibility.
  • Remove now-redundant ARKIME_RETURN_IF_DNS_PORT calls from in-tree parsers (bacnet, dnp3, gtp, misc, pana, rdp, synchrophasor).

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…3932)

- parsers.c: in arkime_parsers_classify_udp, skip the byte-based
  classifier dispatch (Udp0/Udp1/Udp2) when either side of the session
  is on UDP/53.  Port-based classifiers still run, so dns.c is
  unaffected.  Parsers that legitimately need to run on UDP/53 should
  register a port-based classifier.
- arkime.h: mark ARKIME_RETURN_IF_DNS_PORT as deprecated; keep the
  macro for out-of-tree parser compatibility.
- Remove now-redundant ARKIME_RETURN_IF_DNS_PORT calls from in-tree
  parsers (bacnet, dnp3, gtp, misc, pana, rdp, synchrophasor).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
@awick awick merged commit 8fafadd into main Apr 30, 2026
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@awick awick deleted the udp-skip-dns-port branch April 30, 2026 12:22
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