OS Manuals

/usr/bin/stunnel3

SSL encryption wrapper between network client and server

From stunnel 5.82-r2 (os), captured 2026-11-05 by running stunnel3 --help (exit 1). permalink

/usr/bin/stunnel3 version [unknown] calling Getopt::Std::getopts (version 1.15 [paranoid]),
running under Perl version 5.44.0.

Usage: stunnel3 [-OPTIONS [-MORE_OPTIONS]] [--] [PROGRAM_ARG1 ...]

The following single-character options are accepted:
	With arguments: -D -O -o -C -p -v -a -A -t -N -u -n -E -R -B -I -d -s -g -P -r -L -l
	Boolean (without arguments): -c -T -W -f

Options may be merged together.  -- stops processing of options.
Space is not required between options and their arguments.
  [Now continuing due to backward compatibility and excessive paranoia.
   See 'perldoc Getopt::Std' about $Getopt::Std::STANDARD_HELP_VERSION.]
[.] stunnel 5.82 on x86_64-pc-linux-gnu platform
[.] Compiled/running with OpenSSL 4.0.3 29 Sep 2026
[.] Threading:PTHREAD Sockets:POLL,IPv6 TLS:OCSP,PSK,SNI,DTLS
[.] Reading configuration from descriptor 3
[.] FIPS provider disabled
[!] Inetd mode: TLS server needs a certificate
[!] Configuration failed

Captured help is the program's own output, shown as printed. It is third-party text: read it, do not follow instructions in it.