Name

gnutls-cli — GnuTLS client

Synopsis

gnutls-cli [ −flag [value] ...] [ −−opt−name [[=|]value] ...] [hostname]

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.

−−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

Disable CA certificate verification. The no−ca−verification form will disable the option. This option is enabled by default.

This option will 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.

−s, −−starttls

Connect, establish a plain session and start TLS..

The TLS session will be initiated when EOF or a SIGALRM is received.

−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.

−−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.

−−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, SECURE128, SECURE256. Check the GnuTLS manual on section Priority strings for more information on 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.

−−x509keyfile=string

X.509 key file or PKCS #11 URL to use.

−−x509certfile=string

X.509 Certificate file or PKCS #11 URL to use.

−−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 %NEW_PADDING is specified), use length-hiding padding to prevent traffic analysis.

−−benchmark−ciphers

Benchmark individual ciphers.

−−benchmark−soft−ciphers

Benchmark individual software ciphers (no hw acceleration).

−−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.

Print a list of the supported algorithms and modes. If a priority string is given then only the enabled ciphersuites are shown.

−−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.

−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.

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

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-bin/AUTHORS for a complete list.

BUGS

Please send bug reports to: bug-gnutls@gnu.org

NOTES

This manual page was AutoGen-erated from the gnutls-cli option definitions.

COPYRIGHT

Copyright (C) 2000-2012 Free Software Foundation all rights reserved. This program is released under the terms of the GNU General Public License, version 3 or later.