Provided by: gnutls-bin_3.5.18-1ubuntu1.6_amd64 
NAME
gnutls-cli - GnuTLS client
SYNOPSIS
gnutls-cli [-flags] [-flag [value]] [--option-name[[=| ]value]] [hostname]
Operands and options may be intermixed. They will be reordered.
DESCRIPTION
Simple client program to set up a TLS connection to some other computer. It sets up a TLS connection and
forwards data from the standard input to the secured socket and vice versa.
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.
--tofu, --no-tofu Enable trust on first use authentication. The no-tofu form will disable the option.
This option will, in addition to certificate authentication, perform authentication based on previously
seen public keys, a model similar to SSH authentication. Note that when tofu is specified (PKI) and DANE
authentication will become advisory to assist the public key acceptance process.
--strict-tofu, --no-strict-tofu Fail to connect if a known certificate has changed. The no-strict-tofu
form will disable the option.
This option will perform authentication as with option --tofu; however, while --tofu asks whether to
trust a changed public key, this option will fail in case of public key changes.
--dane, --no-dane Enable DANE certificate verification (DNSSEC). The no-dane form will disable the
option.
This option will, in addition to certificate authentication using the trusted CAs, verify the server
certificates using on the DANE information available via DNSSEC.
--local-dns, --no-local-dns Use the local DNS server for DNSSEC resolving. The no-local-dns form will
disable the option.
This option will use the local DNS server for DNSSEC. This is disabled by default due to many servers
not allowing DNSSEC.
--ca-verification, --no-ca-verification Enable CA certificate verification. The no-ca-verification form
will disable the option. This option is enabled by default.
This option can be used to enable or disable CA certificate verification. It is to be used with the
--dane or --tofu options.
--ocsp, --no-ocsp Enable OCSP certificate verification. The no-ocsp form will disable the option.
This option will enable verification of the peer's certificate using ocsp
-r, --resume Establish a session and resume.
Connect, establish a session, reconnect and resume.
-e, --rehandshake Establish a session and rehandshake.
Connect, establish a session and rehandshake immediately.
--sni-hostname=string Server's hostname for server name indication extension.
Set explicitly the server name used in the TLS server name indication extension. That is useful when
testing with servers setup on different DNS name than the intended. If not specified, the provided
hostname is used.
-s, --starttls Connect, establish a plain session and start TLS.
The TLS session will be initiated when EOF or a SIGALRM is received.
--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, lmtp, pop3, nntp, sieve, postgres). This option must not appear in
combination with any of the following options: starttls.
Specify the application layer protocol for STARTTLS. If the protocol is supported, gnutls-cli will
proceed to the TLS negotiation.
-u, --udp Use DTLS (datagram TLS) over UDP.
--mtu=number Set MTU for datagram TLS. This option takes an integer number as its argument. The value
of number is constrained to being:
in the range 0 through 17000
--crlf Send CR LF instead of LF.
--fastopen Enable TCP Fast Open.
--x509fmtder Use DER format for certificates to read from.
-f, --fingerprint Send the openpgp fingerprint, instead of the key.
--print-cert Print peer's certificate in PEM format.
--save-cert=string Save the peer's certificate chain in the specified file in PEM format.
--save-ocsp=string Save the peer's OCSP status response in the provided file.
--dh-bits=number The minimum number of bits allowed for DH. This option takes an integer number as its
argument.
This option sets the minimum number of bits allowed for a Diffie-Hellman key exchange. You may want to
lower the default value if the peer sends a weak prime and you get an connection error with unacceptable
prime.
--priority=string Priorities string.
TLS algorithms and protocols to enable. You can use predefined sets of ciphersuites such as PERFORMANCE,
NORMAL, PFS, SECURE128, SECURE256. The default is NORMAL.
Check the GnuTLS manual on section “Priority strings” for more information on the allowed keywords
--x509cafile=string Certificate file or PKCS #11 URL to use.
--x509crlfile=file CRL file to use.
--pgpkeyfile=file PGP Key file to use.
--pgpkeyring=file PGP Key ring file to use.
--pgpcertfile=file PGP Public Key (certificate) file to use. This option must appear in combination with
the following options: pgpkeyfile.
--x509keyfile=string X.509 key file or PKCS #11 URL to use.
--x509certfile=string X.509 Certificate file or PKCS #11 URL to use. This option must appear in
combination with the following options: x509keyfile.
--pgpsubkey=string PGP subkey to use (hex or auto).
--srpusername=string SRP username to use.
--srppasswd=string SRP password to use.
--pskusername=string PSK username to use.
--pskkey=string PSK key (in hex) to use.
-p string, --port=string The port or service to connect to.
--insecure Don't abort program if server certificate can't be validated.
--ranges Use length-hiding padding to prevent traffic analysis.
When possible (e.g., when using CBC ciphersuites), use length-hiding padding to prevent traffic analysis.
--benchmark-ciphers Benchmark individual ciphers.
By default the benchmarked ciphers will utilize any capabilities of the local CPU to improve performance.
To test against the raw software implementation set the environment variable GNUTLS_CPUID_OVERRIDE to
0x1.
--benchmark-tls-kx Benchmark TLS key exchange methods.
--benchmark-tls-ciphers Benchmark TLS ciphers.
By default the benchmarked ciphers will utilize any capabilities of the local CPU to improve performance.
To test against the raw software implementation set the environment variable GNUTLS_CPUID_OVERRIDE to
0x1.
-l, --list Print a list of the supported algorithms and modes. This option must not appear in
combination with any of the following options: port.
Print a list of the supported algorithms and modes. If a priority string is given then only the enabled
ciphersuites are shown.
--priority-list Print a list of the supported priority strings.
Print a list of the supported priority strings. The ciphersuites corresponding to each priority string
can be examined using -l -p.
--noticket Don't allow session tickets.
--srtp-profiles=string Offer SRTP profiles.
--alpn=string Application layer protocol. This option may appear an unlimited number of times.
This option will set and enable the Application Layer Protocol Negotiation (ALPN) in the TLS protocol.
-b, --heartbeat Activate heartbeat support.
--recordsize=number The maximum record size to advertize. This option takes an integer number as its
argument. The value of number is constrained to being:
in the range 0 through 4096
--disable-sni Do not send a Server Name Indication (SNI).
--disable-extensions Disable all the TLS extensions.
This option disables all TLS extensions. Deprecated option. Use the priority string.
--inline-commands Inline commands of the form ^<cmd>^.
Enable inline commands of the form ^<cmd>^. The inline commands are expected to be in a line by
themselves. The available commands are: resume and renegotiate.
--inline-commands-prefix=string Change the default delimiter for inline commands..
Change the default delimiter (^) used for inline commands. The delimiter is expected to be a single US-
ASCII character (octets 0 - 127). This option is only relevant if inline commands are enabled via the
inline-commands option
--provider=file Specify the PKCS #11 provider library.
This will override the default options in /etc/gnutls/pkcs11.conf
--fips140-mode Reports the status of the FIPS140-2 mode in gnutls library.
-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
Connecting using PSK authentication
To connect to a server using PSK authentication, you need to enable the choice of PSK by using a
cipher priority parameter such as in the example below.
$ ./gnutls-cli -p 5556 localhost --pskusername psk_identity --pskkey 88f3824b3e5659f52d00e959bacab954b6540344 --priority NORMAL:-KX-ALL:+ECDHE-PSK:+DHE-PSK:+PSK
Resolving 'localhost'...
Connecting to '127.0.0.1:5556'...
- PSK authentication.
- Version: TLS1.1
- Key Exchange: PSK
- Cipher: AES-128-CBC
- MAC: SHA1
- Compression: NULL
- Handshake was completed
- Simple Client Mode:
By keeping the --pskusername parameter and removing the --pskkey parameter, it will query only for
the password during the handshake.
Connecting to STARTTLS services
You could also use the client to connect to services with starttls capability.
$ gnutls-cli --starttls-proto smtp --port 25 localhost
Listing ciphersuites in a priority string
To list the ciphersuites in a priority string:
$ ./gnutls-cli --priority SECURE192 -l
Cipher suites for SECURE192
TLS_ECDHE_ECDSA_AES_256_CBC_SHA384 0xc0, 0x24 TLS1.2
TLS_ECDHE_ECDSA_AES_256_GCM_SHA384 0xc0, 0x2e TLS1.2
TLS_ECDHE_RSA_AES_256_GCM_SHA384 0xc0, 0x30 TLS1.2
TLS_DHE_RSA_AES_256_CBC_SHA256 0x00, 0x6b TLS1.2
TLS_DHE_DSS_AES_256_CBC_SHA256 0x00, 0x6a TLS1.2
TLS_RSA_AES_256_CBC_SHA256 0x00, 0x3d TLS1.2
Certificate types: CTYPE-X.509
Protocols: VERS-TLS1.2, VERS-TLS1.1, VERS-TLS1.0, VERS-SSL3.0, VERS-DTLS1.0
Compression: COMP-NULL
Elliptic curves: CURVE-SECP384R1, CURVE-SECP521R1
PK-signatures: SIGN-RSA-SHA384, SIGN-ECDSA-SHA384, SIGN-RSA-SHA512, SIGN-ECDSA-SHA512
Connecting using a PKCS #11 token
To connect to a server using a certificate and a private key present in a PKCS #11 token you need
to substitute the PKCS 11 URLs in the x509certfile and x509keyfile parameters.
Those can be found using "p11tool --list-tokens" and then listing all the objects in the needed
token, and using the appropriate.
$ p11tool --list-tokens
Token 0:
URL: pkcs11:model=PKCS15;manufacturer=MyMan;serial=1234;token=Test
Label: Test
Manufacturer: EnterSafe
Model: PKCS15
Serial: 1234
$ p11tool --login --list-certs "pkcs11:model=PKCS15;manufacturer=MyMan;serial=1234;token=Test"
Object 0:
URL: pkcs11:model=PKCS15;manufacturer=MyMan;serial=1234;token=Test;object=client;type=cert
Type: X.509 Certificate
Label: client
ID: 2a:97:0d:58:d1:51:3c:23:07:ae:4e:0d:72:26:03:7d:99:06:02:6a
$ MYCERT="pkcs11:model=PKCS15;manufacturer=MyMan;serial=1234;token=Test;object=client;type=cert"
$ MYKEY="pkcs11:model=PKCS15;manufacturer=MyMan;serial=1234;token=Test;object=client;type=private"
$ export MYCERT MYKEY
$ gnutls-cli www.example.com --x509keyfile $MYKEY --x509certfile $MYCERT
Notice that the private key only differs from the certificate in the type.
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-debug(1), gnutls-serv(1)
AUTHORS
Nikos Mavrogiannopoulos, Simon Josefsson and others; see /usr/share/doc/gnutls/AUTHORS for a complete
list.
COPYRIGHT
Copyright (C) 2000-2018 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 option definitions.
3.5.18 2022-08-02 gnutls-cli(1)