Registered in 2004 as "Streamlined Blackhole"; no specification was ever published.
IANA assigns 1039 to sbl, "Streamlined Blackhole", registered in November 2004 to an individual with no reference document attached. Despite the name's resemblance to the Spamhaus SBL blocklist, the registry gives no relationship between the two and no protocol description, so nothing further can be stated honestly. In practice an open 1039 is another low-range dynamic port, commonly an RPC endpoint on Windows systems predating Vista.
Expose with care
Undocumented registration; the port number gives you no information, so identify the process behind any open 1039.
$ nc -vz TARGET 1039Seen this on your network? Beige Box scans your Wi-Fi and shows every open port on every device — and its Ports tool links straight back here.
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Corrections or a missing port? Reply @rimrocksystems.