i7mail.net
Issued by Let's Encrypt Authority X3
About this certificate
This digital certificate with serial number 03:0c:ef:6b:40:13:8c:d4:e2:2b:d0:97:c2:18:fd:78:c8:7e was issued on by Let's Encrypt.
With 4 subject alternative names this certificate can be used to secure multiple fqdn's. This certificate has already expired and will cause a warning or error message in the browser it's still listed on this site to allow you to look back on previously issued certificates. If we have found any compliance issues with this certificate they will be shown below. I hope this certificate review is providing you the detailed information in a simple form you where looking for.
We have idenified some issues with this certificate:
- Subscriber Certificate: commonName is deprecated. (BRs: 7.1.4.2.2)
Certificate Subject
CN=i7mail.net
Let's Encrypt
Organization:
Let's Encrypt
Country:
US
This certificate has expire since
Certificate Details
Serial Number (hex): 03:0c:ef:6b:40:13:8c:d4:e2:2b:d0:97:c2:18:fd:78:c8:7eSerial Number (int): 265738488564711594604802198424604647147646
Serial Number lenght: 138 bits, 18 octets
SubjectKeyId: 10:9d:da:ec:d3:10:9f:56:8a:04:b2:9a:ee:f3:63:5f:2a:c6:82:81
AuthorityKeyId: a8:4a:6a:63:04:7d:dd:ba:e6:d1:39:b7:a6:45:65:ef:f3:a8:ec:a1
Fingerprint (sha1): bb:e3:87:f1:4c:86:37:3c:c8:99:04:06:d5:9a:96:77:5c:da:0b:46
Fingerprint (sha256): f1:8e:f4:06:29:8f:fb:86:d3:e6:a4:3b:a0:06:7e:5b:f9:eb:92:17:32:e1:c7:2f:51:99:46:68:40:46:25:e3
Issuing Certificate URL: http://cert.int-x3.letsencrypt.org/
Revocation information
OCSP Server: http://ocsp.int-x3.letsencrypt.orgCheck the revocation status for certificate i7mail.net
4
DNS Names
0
Email Addresses
0
IP Addresses
Advanced Certificate Properties
Tehnical certificate details for i7mail.net
Public Key Algorithm
RSA
Key Size
2048
Signature Algorithm
SHA256 with RSA
Key Usage
Digital Signature
Key Encipherment
Extended Key Usages
Server Authentication
Client Authentication
Extensions
9 extensions
No
unhandled critical extensions
CA Certificate
This is not a CA certificate
Subject Alternative Names
i7mail.com
i7mail.net
www.i7mail.com
www.i7mail.net
i7mail.net
www.i7mail.com
www.i7mail.net
Other certificates including the domain name i7mail.net
(limited to 100 certificates)
i7mail.net
i7mail.net
pro.i7mail.net
i7mail.net
i7mail.net
filter.i7mail.net
filter.i7mail.net
*.i7mail.net
i7mail.net
i7mail.net
pro.i7mail.net
pro.i7mail.net
pro.i7mail.net
i7mail.net
i7mail.net
pro.i7mail.net
pro.i7mail.net
i7mail.net
i7mail.net
i7mail.net
pro.i7mail.net
*.i7mail.net
pro.i7mail.net
i7mail.net
pro.i7mail.net
pro.i7mail.net
i7mail.net
filter.i7mail.net
*.i7mail.net
i7mail.net
i7mail.net
i7mail.net
i7mail.net
*.i7mail.net
pro.i7mail.net
i7mail.net
i7mail.net
i7mail.net
pro.i7mail.net
i7mail.net
i7mail.net
i7mail.net
i7mail.net
pro.i7mail.net
i7mail.net
pro.i7mail.net
pro.i7mail.net
pro.i7mail.net
i7mail.net
i7mail.net
pro.i7mail.net
*.i7mail.net
i7mail.net
pro.i7mail.net
i7mail.net
filter.i7mail.net
i7mail.net
pro.i7mail.net
i7mail.net
i7mail.net
filter.i7mail.net
filter.i7mail.net
*.i7mail.net
i7mail.net
i7mail.net
pro.i7mail.net
pro.i7mail.net
pro.i7mail.net
i7mail.net
i7mail.net
pro.i7mail.net
pro.i7mail.net
i7mail.net
i7mail.net
i7mail.net
pro.i7mail.net
*.i7mail.net
pro.i7mail.net
i7mail.net
pro.i7mail.net
pro.i7mail.net
i7mail.net
filter.i7mail.net
*.i7mail.net
i7mail.net
i7mail.net
i7mail.net
i7mail.net
*.i7mail.net
pro.i7mail.net
i7mail.net
i7mail.net
i7mail.net
pro.i7mail.net
i7mail.net
i7mail.net
i7mail.net
i7mail.net
pro.i7mail.net
i7mail.net
pro.i7mail.net
pro.i7mail.net
pro.i7mail.net
i7mail.net
i7mail.net
pro.i7mail.net
*.i7mail.net
i7mail.net
pro.i7mail.net
i7mail.net
filter.i7mail.net
Certificate
The complete raw certificate details for i7mail.net in PEM and ASN.1 format.
Certificate (PEM)
-----BEGIN CERTIFICATE----- MIIFeTCCBGGgAwIBAgISAwzva0ATjNTiK9CXwhj9eMh+MA0GCSqGSIb3DQEBCwUA MEoxCzAJBgNVBAYTAlVTMRYwFAYDVQQKEw1MZXQncyBFbmNyeXB0MSMwIQYDVQQD ExpMZXQncyBFbmNyeXB0IEF1dGhvcml0eSBYMzAeFw0yMDAyMDUwOTM0MjJaFw0y MDA1MDUwOTM0MjJaMBUxEzARBgNVBAMTCmk3bWFpbC5uZXQwggEiMA0GCSqGSIb3 DQEBAQUAA4IBDwAwggEKAoIBAQCyAM0EzNFJXMb476YpC927JCd0IPaaR+8GAL91 4ZOg8NCfv8NfFhNAvN3lRxtpbM5XwX35Zm7QVDjqyMX3TB0K7s1vf4YA7Mt6YRUn 2I6I+Y+k9it508TJu/pltB/o1bpjo61NUHuWFoCAA9tb71M52pJkAOEJ5iIR958M HixOGoyLhrVtYsZRX9yMXwH6rLGD89zN32pfGwqgTESkTtlNYA/ND3Lja/NP1OD8 bG9ZyhsPZuhwOWpSX3e55LOG2LiGOQ2fjlWzOuxgcLFF4De0dq1jeZUNkAiX5iEP NI7Bvk03IDAp5+IFwrt8gZ1FVf8y+xiRy4BxyVLeELG0xaTbAgMBAAGjggKMMIIC iDAOBgNVHQ8BAf8EBAMCBaAwHQYDVR0lBBYwFAYIKwYBBQUHAwEGCCsGAQUFBwMC MAwGA1UdEwEB/wQCMAAwHQYDVR0OBBYEFBCd2uzTEJ9WigSymu7zY18qxoKBMB8G A1UdIwQYMBaAFKhKamMEfd265tE5t6ZFZe/zqOyhMG8GCCsGAQUFBwEBBGMwYTAu BggrBgEFBQcwAYYiaHR0cDovL29jc3AuaW50LXgzLmxldHNlbmNyeXB0Lm9yZzAv BggrBgEFBQcwAoYjaHR0cDovL2NlcnQuaW50LXgzLmxldHNlbmNyeXB0Lm9yZy8w QQYDVR0RBDowOIIKaTdtYWlsLmNvbYIKaTdtYWlsLm5ldIIOd3d3Lmk3bWFpbC5j b22CDnd3dy5pN21haWwubmV0MEwGA1UdIARFMEMwCAYGZ4EMAQIBMDcGCysGAQQB gt8TAQEBMCgwJgYIKwYBBQUHAgEWGmh0dHA6Ly9jcHMubGV0c2VuY3J5cHQub3Jn MIIBBQYKKwYBBAHWeQIEAgSB9gSB8wDxAHcAsh4FzIuizYogTodm+Su5iiUgZ2va +nDnsklTLe+LkF4AAAFwFOpEQwAABAMASDBGAiEAnRF3wwXn/jwpPcNUc7im0oWC 1xXEj47lvhAWwqIUTXACIQClBYGQElXOYmKu8qg+P22sm9hHNAdSK2P38EVczo7D qAB2AG9Tdqwx8DEZ2JkApFEV/3cVHBHZAsEAKQaNsgiaN9kTAAABcBTqRHAAAAQD AEcwRQIgJwUPDxokywWXaZhDVGB2wXe2lCbdwv5ClaQfB+RunbECIQCiChLfiAkP 4hiz8T+Fk13xgtIr3ckypneZVHn6jmZhRjANBgkqhkiG9w0BAQsFAAOCAQEALRHF ZtWM2jEoScAmhQ1ejXHfwTpA/094Hr7YxeHiYkgONFjPNQ/FBkK0K6mHODWlYzIq fhmqiiYFqkfhCxQRbgoo9WXV5LJFiNmyuXDcwyr69+gQ5HK4N/hwaK8t2jXBuFmd tQc/gS8wgnDa0ojDUPwmLD4ZvnlTfeYEoC7WrStIMpQdLNFt+lPv9nMqyZw70GUg LzvNVxj8Qyz30+vMNp9huNEA78ckc3mkg2tjKOhQXf7mENONw12e2cnRmNQBjSkv oClG2biwJWaKt+b9drNYGUS/EX23ulPol6LbGdTaemHYxTpCVs4PpnP+YeqKZZHg Lb/aQNh4sQ2U15/7Fw== -----END CERTIFICATE-----
Public Key (PEM)
-----BEGIN PUBLIC KEY----- MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAsgDNBMzRSVzG+O+mKQvd uyQndCD2mkfvBgC/deGToPDQn7/DXxYTQLzd5UcbaWzOV8F9+WZu0FQ46sjF90wd Cu7Nb3+GAOzLemEVJ9iOiPmPpPYredPEybv6ZbQf6NW6Y6OtTVB7lhaAgAPbW+9T OdqSZADhCeYiEfefDB4sThqMi4a1bWLGUV/cjF8B+qyxg/Pczd9qXxsKoExEpE7Z TWAPzQ9y42vzT9Tg/GxvWcobD2bocDlqUl93ueSzhti4hjkNn45VszrsYHCxReA3 tHatY3mVDZAIl+YhDzSOwb5NNyAwKefiBcK7fIGdRVX/MvsYkcuAcclS3hCxtMWk 2wIDAQAB -----END PUBLIC KEY-----
ASN.1 decoded
[c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . [c:2|t:0|true] OtherName . . . . . . . . . . . . [c:0|t:2|false] INTEGER 2 . . . . . . . . [c:0|t:2|false] INTEGER 265738488564711594604802198424604647147646 . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.2.840.113549.1.1.11 (sha256WithRSAEncryption) . . . . . . . . . . . . [c:0|t:5|false] NULL . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.6 (countryName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'US' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.10 (organizationName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Let's Encrypt' . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.3 (commonName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'Let's Encrypt Authority X3' . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2020-02-05 09:34:22 +0000 UTC . . . . . . . . . . . . [c:0|t:23|false] UTCTime 2020-05-05 09:34:22 +0000 UTC . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:17|true] SET, SET OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.4.3 (commonName) . . . . . . . . . . . . . . . . . . . . [c:0|t:19|false] PrintableString 'i7mail.net' . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.2.840.113549.1.1.1 (rsaEncryption) . . . . . . . . . . . . . . . . [c:0|t:5|false] NULL . . . . . . . . . . . . [c:0|t:3|false] BIT STRING (2160 bits) . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:2|false] INTEGER 22470813200027770988830343218481422340485691649814584525658372692243230715917764303138334906098258958595533840694067681317718771445851146391498247697806481373988007339640188329129052919982344892986922194751839136021687321475934936609420767849002493661282294731891924467036896441102718416159502130832031504381936763062338807829484134308859641639410202886699238761472280746028241116139931662179407616898534359009136309945356901687714375621760411048587908579734425195583894625205216329084905898658409450379941674555508761915905913515470124338535487012366727979788489689340939043634272063441549283642529582241914630284507 . . . . . . . . . . . . . . . . . . . . [c:0|t:2|false] INTEGER 65537 . . . . . . . . [c:2|t:3|true] ORAddress . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.15 (keyUsage) . . . . . . . . . . . . . . . . . . . . [c:0|t:1|false] BOOLEAN true . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (4 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:3|false] BIT STRING (3 bits) 05a0 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.37 (extKeyUsage) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (22 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.3.1 (serverAuth) . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.3.2 (clientAuth) . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.19 (basicConstraints) . . . . . . . . . . . . . . . . . . . . [c:0|t:1|false] BOOLEAN true . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (2 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.14 (subjectKeyIdentifier) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (22 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (20 bytes) 109ddaecd3109f568a04b29aeef3635f2ac68281 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.35 (authorityKeyIdentifier) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (24 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:0|false] OtherName a84a6a63047dddbae6d139b7a64565eff3a8eca1 . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.1.1 (authorityInfoAccess) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (99 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.48.1 (ocsp) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:6|false] IA5String 'http://ocsp.int-x3.letsencrypt.org' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.48.2 (caIssuers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:6|false] IA5String 'http://cert.int-x3.letsencrypt.org/' . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.17 (subjectAltName) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (58 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'i7mail.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'i7mail.net' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.i7mail.com' . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:2|t:2|false] IA5String 'www.i7mail.net' . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.5.29.32 (certificatePolicies) . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (69 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 2.23.140.1.2.1 (Domain Validation Certificates Policy) . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.4.1.44947.1.1.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.5.5.7.2.1 (cps) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:22|false] IA5String 'http://cps.letsencrypt.org' . . . . . . . . . . . . . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . . . . . . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.3.6.1.4.1.11129.2.4.2 . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (246 bytes) . . . . . . . . . . . . . . . . . . . . . . . . [c:0|t:4|false] OCTET STRING (243 bytes) 00f1007700b21e05cc8ba2cd8a204e8766f92bb98a2520676bdafa70e7b249532def8b905e0000017014ea444300000403004830460221009d1177c305e7fe3c293dc35473b8a6d28582d715c48f8ee5be1016c2a2144d70022100a50581901255ce6262aef2a83e3f6dac9bd8473407522b63f7f0455cce8ec3a80076006f5376ac31f03119d89900a45115ff77151c11d902c10029068db2089a37d9130000017014ea44700000040300473045022027050f0f1a24cb0597699843546076c177b69426ddc2fe4295a41f07e46e9db1022100a20a12df88090fe218b3f13f85935df182d22bddc932a677995479fa8e666146 . . . . [c:0|t:16|true] SEQUENCE, SEQUENCE OF . . . . . . . . [c:0|t:6|false] OBJECT IDENTIFIER 1.2.840.113549.1.1.11 (sha256WithRSAEncryption) . . . . . . . . [c:0|t:5|false] NULL . . . . [c:0|t:3|false] BIT STRING (2048 bits) 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