Connection Reports

Connection Reports

A report is the file written by /cnt <number>. It contains everything the server could tell about that connection, grouped into sections.

Where reports are saved

plugins/connection-verify/<file.folder>/<number>.<ext>

• <file.folder> defaults to connection
• <ext> is txt or json depending on file.format

Which connections get a number

A connection is rejected/lost at exactly one stage, so each attempt yields exactly one number (normal quits are never counted as failures).

Stage	Event / source	Examples
Successful join	PlayerJoinEvent	a normal join
Pre-login	AsyncPlayerPreLoginEvent	ban, whitelist, server full
Login	PlayerLoginEvent	plugin disallows the login
Connection dropped	PlayerConnectionCloseEvent	network errors, timeouts, generic disconnects after auth but before joining
Raw drop	server log (Log4j2 watcher)	nameless sockets logged as /<ip>:<port> lost connection: …, closed before any profile exists (e.g. "Connection failed. Please try again or contact an administrator.")

The raw-drop stage has no Bukkit event — those connections die before a name or profile exists — so Connection Verify reads them from the server log through a lightweight Log4j2 appender on the root logger (toggle with logging.network-drops). The leading / distinguishes a nameless raw drop from a named disconnect, so a connection is never counted twice.

Limitation: a drop is numbered only if the server logs a lost connection line for it. A handshake closed so early that the server writes no log line at all (for example some incompatible-version cases) still cannot be observed.

Sections

Section	Examples of fields
Capture	event, capturing thread, primary-thread flag
Identity	name, display/list name, UUID (+version), skin/cape texture URLs, profile signature
Network	IP, port, virtual host, brand, protocol, ping, view/sim distance, transfer flag
Client options	locale, main hand, chat & particle visibility, skin parts
Session	first join, first played, last login/seen, op, whitelist, ban, game mode
Player state	health, hunger, XP, movement, pose, air, fire, freeze, potion effects, …
Attributes	every applicable attribute (value + base)
Equipment & inventory	armor, hands, held slot, used slots, ender chest
Location	coordinates, facing, biome, light, chunk, respawn/death points
World	difficulty, weather, time, moon phase, border, counts
Result (failures)	login stage, result, kick message; for drops also the disconnect reason, its category and likely cause, and any exception from the log
Server	versions, MOTD, TPS, MSPT, op/whitelist/ban counts, worlds, plugins
Runtime / Environment	Java, OS, memory, GC, threads, classes, uptime
System / hardware	CPU load, physical & swap memory, committed virtual memory, process info, network interfaces
JVM details	runtime/spec versions, VM flags, JIT, memory managers & pools

Each section can be toggled in Configuration under capture.*.

Defensive capture

Every field is read defensively. A value that is unavailable on the running server build is shown as (unavailable: <Reason>), and missing values as (unknown). A single failing field never aborts the report.

Formats

• text — an aligned, human-readable report (default).
• json — pretty-printed JSON with the same data, ideal for log pipelines / SIEMs. Set file.format: json.

Retention

Connection numbers live in memory only. Tune records.max-in-memory and records.expire-after-minutes in Configuration. Save a report with /cnt while the server is still running.