SSL-Tools

SSL check results of mail.proton.me

NEW You can also bulk check multiple servers.

Discover if the mail servers for mail.proton.me can be reached through a secure connection.

To establish a secure connection a mail server has to offer STARTTLS (SSL), a trustworthy SSL certificate, support for the Diffie-Hellman-Algorithm to guarantee Perfect Forward Secrecy and must not be vulnerable against the Heartbleed attack. Futhermore we recommend using end-to-end encryption with GnuPG.

Summary

JSON Refresh

Report created Mon, 16 Feb 2026 17:12:43 +0000

The mailservers of mail.proton.me can be reached through a secure connection.

Servers

Incoming Mails

These servers are responsible for incoming mails to @mail.proton.me addresses.

Hostname / IP address Priority STARTTLS Certificates Protocol
mail.protonmail.ch
185.70.42.128
 10
supported
protonmail.com
DANE
valid
PFS
supported
Heartbleed
not vulnerable
Weak ciphers
not found
  • TLSv1.2
  • SSLv3
31 s
mail.protonmail.ch
176.119.200.128
 10
supported
protonmail.com
DANE
valid
PFS
supported
Heartbleed
not vulnerable
Weak ciphers
not found
  • TLSv1.2
  • SSLv3
31 s
mail.protonmail.ch
185.205.70.128
 10
supported
protonmail.com
DANE
valid
PFS
supported
Heartbleed
not vulnerable
Weak ciphers
not found
  • TLSv1.2
  • SSLv3
36 s
mailsec.protonmail.ch
185.70.42.129
 20
supported
protonmail.com
DANE
valid
PFS
supported
Heartbleed
not vulnerable
Weak ciphers
not found
  • TLSv1.2
  • SSLv3
26 s
mailsec.protonmail.ch
176.119.200.129
 20
supported
protonmail.com
DANE
valid
PFS
supported
Heartbleed
not vulnerable
Weak ciphers
not found
  • TLSv1.2
  • SSLv3
19 s
mailsec.protonmail.ch
185.205.70.129
 20
supported
protonmail.com
DANE
valid
PFS
supported
Heartbleed
not vulnerable
Weak ciphers
not found
  • TLSv1.2
  • SSLv3
19 s

Outgoing Mails

We have not received any emails from a @mail.proton.me address so far. Test mail delivery

Certificates

First seen at:

CN=protonmail.com

Certificate chain
  • protonmail.com
    • remaining
    • 4096 bit
    • sha256WithRSAEncryption
      • R12
        • remaining
        • 2048 bit
        • sha256WithRSAEncryption
          • ISRG Root X1 (Certificate is self-signed.)
            • remaining
            • 4096 bit
            • sha256WithRSAEncryption
Subject
Common Name (CN)
  • protonmail.com
Alternative Names
  • *.pm.me
  • *.protonmail.ch
  • *.protonmail.com
  • *.protonvpn.ch
  • *.protonvpn.com
  • protonmail.com
Issuer
Country (C)
  • US
Organization (O)
  • Let's Encrypt
Common Name (CN)
  • R12
validity period
Not valid before
2026-01-25
Not valid after
2026-04-25
This certifcate has been verified for the following usages:
  • Digital Signature
  • Key Encipherment
  • TLS Web Server Authentication
  • TLS Web Client Authentication
Fingerprints
SHA256
5E:CE:10:D0:8C:97:F6:A8:2C:34:B0:67:0E:45:77:2F:AF:25:2C:89:81:4F:47:0F:26:59:BD:CE:D4:13:40:02
SHA1
38:F2:42:E6:6E:A1:C4:C0:DE:3A:9E:BC:CE:7C:53:F4:43:2A:4B:A3
X509v3 extensions
subjectKeyIdentifier
  • F1:A2:0A:FF:29:EF:F8:78:84:E8:07:0C:E0:56:8A:76:64:D2:2B:A5
authorityKeyIdentifier
  • keyid:00:B5:29:F2:2D:8E:6F:31:E8:9B:4C:AD:78:3E:FA:DC:E9:0C:D1:D2
authorityInfoAccess
  • CA Issuers - URI:http://r12.i.lencr.org/
certificatePolicies
  • Policy: 2.23.140.1.2.1
crlDistributionPoints
  • Full Name:
  • URI:http://r12.c.lencr.org/91.crl
ct_precert_scts
  • Signed Certificate Timestamp:
  • Version : v1 (0x0)
  • Log ID : 71:7E:95:F3:C2:38:8A:6D:B1:E3:84:49:3D:31:E1:5A:
  • A9:62:08:76:2D:42:00:E0:05:0C:D0:67:B5:A6:61:E2
  • Timestamp : Jan 25 14:21:57.208 2026 GMT
  • Extensions: 00:00:05:00:07:C4:31:DE
  • Signature : ecdsa-with-SHA256
  • 30:46:02:21:00:A5:2F:10:11:55:00:55:DA:BE:AB:13:
  • D5:E5:18:67:6D:26:26:7B:FA:42:45:65:EB:67:0E:3C:
  • 55:02:FD:D7:42:02:21:00:CA:4D:99:3F:52:8C:7C:F8:
  • 21:D6:0D:DB:CC:EC:0C:D6:6E:0A:2A:67:5C:3C:66:B5:
  • 72:81:8A:C0:75:07:05:83
  • Signed Certificate Timestamp:
  • Version : v1 (0x0)
  • Log ID : 96:97:64:BF:55:58:97:AD:F7:43:87:68:37:08:42:77:
  • E9:F0:3A:D5:F6:A4:F3:36:6E:46:A4:3F:0F:CA:A9:C6
  • Timestamp : Jan 25 14:21:59.237 2026 GMT
  • Extensions: none
  • Signature : ecdsa-with-SHA256
  • 30:44:02:20:2C:78:0E:C8:37:C5:87:13:CF:99:97:F8:
  • 34:74:AF:4C:93:57:13:34:67:B3:3D:99:77:31:1D:DC:
  • CD:3D:F5:7E:02:20:4B:8E:5E:9D:24:58:CE:2F:AE:CA:
  • 49:4C:65:6E:69:1B:E2:98:E3:71:B8:C8:4A:16:15:84:
  • E2:A9:B4:04:BA:E9

DANE

DNS-based Authentication of Named Entities (DANE) is a protocol to allow X.509 certificates to be bound to DNS using TLSA records and DNSSEC.

Name Options DNSSEC Matches
_25._tcp.mail.protonmail.ch
  • DANE-EE: Domain Issued Certificate
  • Use subject public key
  • SHA-256 Hash
valid
valid
_25._tcp.mail.protonmail.ch
  • DANE-EE: Domain Issued Certificate
  • Use subject public key
  • SHA-256 Hash
valid
—
_25._tcp.mailsec.protonmail.ch
  • DANE-EE: Domain Issued Certificate
  • Use subject public key
  • SHA-256 Hash
valid
—
_25._tcp.mailsec.protonmail.ch
  • DANE-EE: Domain Issued Certificate
  • Use subject public key
  • SHA-256 Hash
valid
valid