tuyendq@2:~$ apt search gnutls-cli
Sorting... Done
Full Text Search... Done
gnutls-bin/bionic-updates 3.5.18-1ubuntu1.4 amd64
GNU TLS library - commandline utilities
tuyendq@2:~$
sudo apt install gnutls-bin
tuyendq@2:~$ gnutls-cli -p 465 smtp.gmail.com
Processed 129 CA certificate(s).
Resolving 'smtp.gmail.com:465'...
Connecting to '142.250.101.108:465'...
- Certificate type: X.509
- Got a certificate list of 2 certificates.
- Certificate[0] info:
- subject `CN=smtp.gmail.com,O=Google LLC,L=Mountain View,ST=California,C=US', issuer `CN=GTS CA 1O1,O=Google Trust Services,C=US', serial 0x5645821e254664ef0300000000cbf788, EC/ECDSA key 256 bits, signed using RSA-SHA256, activated `2021-04-13 10:15:55 UTC', expires `2021-07-06 10:15:54 UTC', pin-sha256="xY1LhV4Bv7CqYxSWp+DZql+kGylKKwwuJvuSWVSK8pU="
Public Key ID:
sha1:94589a11b6767e7ba6ac53c924f32f78ab9101cf
sha256:c58d4b855e01bfb0aa631496a7e0d9aa5fa41b294a2b0c2e26fb9259548af295
Public Key PIN:
pin-sha256:xY1LhV4Bv7CqYxSWp+DZql+kGylKKwwuJvuSWVSK8pU=
Public key's random art:
+--[SECP256R1]----+
| +.. |
| . B . |
| B + |
| . Bo . |
| E*.. |
| +=. |
| oo..o |
| ooo+. |
| o=+o |
+-----------------+
- Certificate[1] info:
- subject `CN=GTS CA 1O1,O=Google Trust Services,C=US', issuer `CN=GlobalSign,O=GlobalSign,OU=GlobalSign Root CA - R2', serial 0x01e3b49aa18d8aa981256950b8, RSA key 2048 bits, signed using RSA-SHA256, activated `2017-06-15 00:00:42 UTC', expires `2021-12-15 00:00:42 UTC', pin-sha256="YZPgTZ+woNCCCIW3LH2CxQeLzB/1m42QcCTBSdgayjs="
- Status: The certificate is trusted.
- Description: (TLS1.2)-(ECDHE-ECDSA-SECP256R1)-(CHACHA20-POLY1305)
- Session ID: 02:60:99:6C:0E:AA:E6:43:16:06:AC:06:B1:94:6E:85:7F:76:AF:B3:E1:A3:B0:F8:FF:8A:BD:63:40:43:53:99
- Ephemeral EC Diffie-Hellman parameters
- Using curve: SECP256R1
- Curve size: 256 bits
- Version: TLS1.2
- Key Exchange: ECDHE-ECDSA
- Server Signature: ECDSA-SHA256
- Cipher: CHACHA20-POLY1305
- MAC: AEAD
- Compression: NULL
- Options: extended master secret, safe renegotiation,
- Handshake was completed
- Simple Client Mode:
220 smtp.gmail.com ESMTP y14sm2123044pjn.48 - gsmtp
ehlo tuyen
250-smtp.gmail.com at your service, [173.82.240.78]
250-SIZE 35882577
250-8BITMIME
250-AUTH LOGIN PLAIN XOAUTH2 PLAIN-CLIENTTOKEN OAUTHBEARER XOAUTH
250-ENHANCEDSTATUSCODES
250-PIPELINING
250-CHUNKING
250 SMTPUTF8