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gnutls-cli(1) User Commands gnutls-cli(1)

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 num, --debug=num
Enable debugging. This option takes an integer number as its
argument. The value of num is constrained to being:
in the range 0 through 9999

Specifies the debug level.

-V, --verbose
More verbose output.

--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 certificate is unknown or a known
certificate has changed. The no-strict-tofu form will disable
the option.

This option will perform authentication as with option --tofu;
however, no questions shall be asked whatsoever, neither to
accept an unknown certificate nor a changed one.

--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.

--earlydata=str
Send early data on resumption from the specified file.

-e, --rehandshake
Establish a session and rehandshake.

Connect, establish a session and rehandshake immediately.

--sni-hostname=str
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. Even with this option server
certificate verification still uses the hostname passed on the
main commandline. Use --verify-hostname to change this.

--verify-hostname=str
Server's hostname to use for validation.

Set explicitly the server name to be used when validating the
server's certificate.

-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=str
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=num
Set MTU for datagram TLS. This option takes an integer number
as its argument. The value of num 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.

--print-cert
Print peer's certificate in PEM format.

--save-cert=str
Save the peer's certificate chain in the specified file in PEM
format.

--save-ocsp=str
Save the peer's OCSP status response in the provided file. This
option must not appear in combination with any of the following
options: save-ocsp-multi.

--save-ocsp-multi=str
Save all OCSP responses provided by the peer in this file. This
option must not appear in combination with any of the following
options: save-ocsp.

The file will contain a list of PEM encoded OCSP status
responses if any were provided by the peer, starting with the
one for the peer's server certificate.

--save-server-trace=str
Save the server-side TLS message trace in the provided file.

--save-client-trace=str
Save the client-side TLS message trace in the provided file.

--dh-bits=num
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=str
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=str
Certificate file or PKCS #11 URL to use.

--x509crlfile=file
CRL file to use.

--x509keyfile=str
X.509 key file or PKCS #11 URL to use.

--x509certfile=str
X.509 Certificate file or PKCS #11 URL to use. This option must
appear in combination with the following options: x509keyfile.

--rawpkkeyfile=str
Private key file (PKCS #8 or PKCS #12) or PKCS #11 URL to use.

In order to instruct the application to negotiate raw public
keys one must enable the respective certificate types via the
priority strings (i.e. CTYPE-CLI-* and CTYPE-SRV-* flags).

Check the GnuTLS manual on section "Priority strings" for
more information on how to set certificate types.

--rawpkfile=str
Raw public-key file to use. This option must appear in
combination with the following options: rawpkkeyfile.

In order to instruct the application to negotiate raw public
keys one must enable the respective certificate types via the
priority strings (i.e. CTYPE-CLI-* and CTYPE-SRV-* flags).

Check the GnuTLS manual on section "Priority strings" for
more information on how to set certificate types.

--srpusername=str
SRP username to use.

--srppasswd=str
SRP password to use.

--pskusername=str
PSK username to use.

--pskkey=str
PSK key (in hex) to use.

-p str, --port=str
The port or service to connect to.

--insecure
Don't abort program if server certificate can't be validated.

--verify-allow-broken
Allow broken algorithms, such as MD5 for certificate
verification.

--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.

NOTE: THIS OPTION IS DEPRECATED

--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.

-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.

Disable the request of receiving of session tickets under TLS1.2
or earlier

--srtp-profiles=str
Offer SRTP profiles.

--alpn=str
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.

--compress-cert=str
Compress certificate. This option may appear an unlimited
number of times.

This option sets a supported compression method for certificate
compression.

-b, --heartbeat
Activate heartbeat support.

--recordsize=num
The maximum record size to advertise. This option takes an
integer number as its argument. The value of num 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.

NOTE: THIS OPTION IS DEPRECATED

--single-key-share
Send a single key share under TLS1.3.

This option switches the default mode of sending multiple key
shares, to send a single one (the top one).

--post-handshake-auth
Enable post-handshake authentication under TLS1.3.

This option enables post-handshake authentication when under
TLS1.3.

--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, rekey1 (local rekey), rekey (rekey on both
peers) and renegotiate.

--inline-commands-prefix=str
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
/usr/local/etc/gnutls/pkcs11.conf

--fips140-mode
Reports the status of the FIPS140-2 mode in gnutls library.

--list-config
Reports the configuration of the library.

--logfile=str
Redirect informational messages to a specific file.

Redirect informational messages to a specific file. The file may
be /dev/null also to make the gnutls client quiet to use it in
piped server connections where only the server communication may
appear on stdout.

--keymatexport=str
Label used for exporting keying material.

--keymatexportsize=num
Size of the exported keying material. This option takes an
integer number as its argument.

--waitresumption
Block waiting for the resumption data under TLS1.3.

This option makes the client to block waiting for the resumption
data under TLS1.3. The option has effect only when --resume is
provided.

--ca-auto-retrieve, --no-ca-auto-retrieve
Enable automatic retrieval of missing CA certificates. The
no-ca-auto-retrieve form will disable the option.

This option enables the client to automatically retrieve the
missing intermediate CA certificates in the certificate chain,
based on the Authority Information Access (AIA) extension.

-v arg, --version=arg
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.

-h, --help
Display usage information and exit.

-!, --more-help
Pass the extended usage information through a pager.

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 using raw public-key authentication
To connect to a server using raw public-key authentication, you need to
enable the option to negotiate raw public-keys via the priority strings
such as in the example below.
$ ./gnutls-cli -p 5556 localhost --priority NORMAL:-CTYPE-CLI-ALL:+CTYPE-CLI-RAWPK --rawpkkeyfile cli.key.pem --rawpkfile cli.rawpk.pem
Processed 1 client raw public key pair...
Resolving 'localhost'...
Connecting to '127.0.0.1:5556'...
- Successfully sent 1 certificate(s) to server.
- Server has requested a certificate.
- Certificate type: X.509
- Got a certificate list of 1 certificates.
- Certificate[0] info:
- skipped
- Description: (TLS1.3-Raw Public Key-X.509)-(ECDHE-SECP256R1)-(RSA-PSS-RSAE-SHA256)-(AES-256-GCM)
- Options:
- Handshake was completed

- Simple Client Mode:

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.

SEE ALSO
gnutls-cli-debug(1), gnutls-serv(1)

BUGS
Please send bug reports to: bugs@gnutls.org

3.7.9 09 Feb 2023 gnutls-cli(1)

DragonFly On-Line Manual Pages

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

EXAMPLES

EXIT STATUS

SEE ALSO

AUTHORS

COPYRIGHT

BUGS