gnutls-cli-debug(1)
NAME
gnutls-cli-debug - GnuTLS debug client
SYNOPSIS
gnutls-cli-debug [-flags] [-flag [value]] [--option-name[[=| ]value]] Operands and options may be intermixed. They will be reordered.
DESCRIPTION
TLS debug client. It sets up multiple TLS connections to a server and queries its capabilities. It was created to assist in debugging GnuTLS, but it might be useful to extract a TLS server's capabilities. It connects to a TLS server, performs tests and print the server's capabilities. If called with the `-v' parameter more checks will be performed. Can be used to check for servers with special needs or bugs.
OPTIONS
-d number, --debug=number
Enable debugging. This option takes an integer number as its
argument. The value of number is constrained to being:
in the range 0 through 9999
Specifies the debug level.
-V, --verbose
More verbose output. This option may appear an unlimited number
of times.
-p number, --port=number
The port to connect to. This option takes an integer number as
its argument. The value of number is constrained to being:
in the range 0 through 65536
--app-proto
This is an alias for the --starttls-proto option.
--starttls-proto=string
The application protocol to be used to obtain the server's
certificate (https, ftp, smtp, imap, ldap, xmpp).
Specify the application layer protocol for STARTTLS. If the
protocol is supported, gnutls-cli will proceed to the TLS
negotiation.
-h, --help
Display usage information and exit.
-!, --more-help
Pass the extended usage information through a pager.
-v [{v|c|n --version [{v|c|n}]}]
Output version of program and exit. The default mode is `v', a
simple version. The `c' mode will print copyright information
and `n' will print the full copyright notice.
EXAMPLES
$ gnutls-cli-debug localhost
GnuTLS debug client 3.5.0
Checking localhost:443
for SSL 3.0 (RFC6101) support... yes
whether we need to disable TLS 1.2... no
whether we need to disable TLS 1.1... no
whether we need to disable TLS 1.0... no
whether %NO_EXTENSIONS is required... no
whether %COMPAT is required... no
for TLS 1.0 (RFC2246) support... yes
for TLS 1.1 (RFC4346) support... yes
for TLS 1.2 (RFC5246) support... yes
fallback from TLS 1.6 to... TLS1.2
for RFC7507 inappropriate fallback... yes
for HTTPS server name... Local
for certificate chain order... sorted
for safe renegotiation (RFC5746) support... yes
for Safe renegotiation support (SCSV)... no
for encrypt-then-MAC (RFC7366) support... no
for ext master secret (RFC7627) support... no
for heartbeat (RFC6520) support... no
for version rollback bug in RSA PMS... dunno
for version rollback bug in Client Hello... no
whether the server ignores the RSA PMS version... yes
whether small records (512 bytes) are tolerated on handshake... yes
whether cipher suites not in SSL 3.0 spec are accepted... yes
whether a bogus TLS record version in the client hello is accepted... yes
whether the server understands TLS closure alerts... partially
whether the server supports session resumption... yes
for anonymous authentication support... no
for ephemeral Diffie-Hellman support... no
for ephemeral EC Diffie-Hellman support... yes
ephemeral EC Diffie-Hellman group info... SECP256R1
for AES-128-GCM cipher (RFC5288) support... yes
for AES-128-CCM cipher (RFC6655) support... no
for AES-128-CCM-8 cipher (RFC6655) support... no
for AES-128-CBC cipher (RFC3268) support... yes
for CAMELLIA-128-GCM cipher (RFC6367) support... no
for CAMELLIA-128-CBC cipher (RFC5932) support... no
for 3DES-CBC cipher (RFC2246) support... yes
for ARCFOUR 128 cipher (RFC2246) support... yes
for MD5 MAC support... yes
for SHA1 MAC support... yes
for SHA256 MAC support... yes
for ZLIB compression support... no
for max record size (RFC6066) support... no
for OCSP status response (RFC6066) support... no
for OpenPGP authentication (RFC6091) support... no
You could also use the client to debug services with starttls
capability.
$ gnutls-cli-debug --starttls-proto smtp --port 25 localhost
EXIT STATUS
One of the following exit values will be returned:
0 (EXIT_SUCCESS)
Successful program execution.
1 (EXIT_FAILURE)
The operation failed or the command syntax was not valid.
70 (EX_SOFTWARE)
libopts had an internal operational error. Please report it to
autogen-users@lists.sourceforge.net. Thank you.
SEE ALSO
gnutls-cli(1), gnutls-serv(1)
AUTHORS
Nikos Mavrogiannopoulos, Simon Josefsson and others; see /usr/share/doc/gnutls/AUTHORS for a complete list.
COPYRIGHT
Copyright (C) 2000-2016 Free Software Foundation, and others all rights reserved. This program is released under the terms of the GNU General Public License, version 3 or later.
BUGS
Please send bug reports to: bugs@gnutls.org
NOTES
This manual page was AutoGen-erated from the gnutls-cli-debug option definitions.
Opportunity
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
Free Books
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Education
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.
