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The JS7 can be configured to send JS7 - NotificationNotifications by mail in case the event of either successful or failed execution of jobs and workflows. In addition, the JS7 - JITL Mail Jobs can be used to send mail. A number of errors can indicate that this the mail server connection does not work:

javax.net.ssl.SSLHandshakeException: No appropriate protocol (protocol is disabled or cipher suites are inappropriate)
javax.mail.MessagingException: Could not connect to SMTP host: mail.example.com, port: 587

javax.net.ssl.SSLException: Unsupported or unrecognized SSL message
javax.mail.MessagingException: Could not connect to SMTP host: mail.example.com, port: 587

javax.mail.AuthenticationFailedException: 535 5.7.3 Authentication unsuccessful

Error messages for notifications The error messages are raised by the JOC Cockpit Cockpit JS7 - Monitor Service when trying to send mail. They can be found in the service-monitor.log file, see JS7 - Log Files and Locations.

Analysis

In the event of problems when using one of the JS7 - JITL Mail Jobs, error messages can be found in the order log or task log and in the joc.log file.

Analysis

For mail configuration there are a number of screws that users can turn. It is important to narrow down recommended that the problem is narrowed down in a systematic way:

• Follow the below steps in the given sequence.
• Do not turn too many screws at the same time. Instead, change one setting then check results by sending mail.
• Do not use mixed settings for different protocols. Instead, choose one protocol and apply settings recommended for that protocol only.

A larger number of e-mail settings is available, see https://javaee.github.io/javamail/docs/api/com/sun/mail/smtp/package-summary.html, however, in most cases they are not related to problems connecting to the a mail server.

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determine_protocol_port_usage determine_protocol_port_usage

Step 1: Determine Protocol and Port Usage

Mail servers frequently use specific ports per type of connection, however, technically protocol used with a connection. However, technically, any port can be used. Your system administrator should provide the information about available protocols and ports:

Below The examples below check availability of TLS port 587, examples can be similarly be applied with to SSL port 465:

# should telnet be available
telnet mail.example.com 587

# should nc or ncat be available
ncat -v -u mail.example.com 587

# should curl be available
curl --ssl --url mail.example.com:587

...

Output of the above commands has to be closely considered in detail if it indicates availability of the respective a port:

# test plain text port
curl --ssl --url mail.example.com:25

# output returned
#   can indicate that the port is not available:
#     curl: (7) Failed to connect to mail.example.com port 25 after 2186 ms: Connection refused
#   can indicate that the port is available: 
#     220 mail.example.com ESMTP Postfix (Debian/GNU)
#     221 2.7.0 Error: I can break rules, too. Goodbye.

# test SMTP over SSL
curl --ssl --url mail.example.com:465
# output returned can indicate that the port is available:
#   curl: (56) Recv failure: Connection reset by peer

# test SMTP over TLS
curl --ssl --url mail.example.com:587
# output returned can indicate that the port is not available:
#   curl: (7) Failed connect to mail.example.com:587; Connection refused

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Depending on the Java version in use, different defaults might be in place, . Users should therefore users should allow/deny use of SSL and /TLS:

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Depending on the Java version in use different defaults might be in place, . Users should therefore users should allow/deny use of SSL and /TLS:

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check_certificates check_certificates

Step 2: Check Certificates

To A server certificate is used to establish a secure connection with a TLS port or SSL port a server certificate is used. The mail server presents its server certificate and the client (JOC Cockpit or command line client) verifies the certificate.
  

...

• For use with OpenSSL certificates are available from /etc/ssl/certs or similar locations.
• For JOC Cockpit operated with Java the certificates are available from the Java cacerts file that which can be found from in different locations depending on the Java version and distribution.
  • For a JDK 1.8 including a JRE provided by OpenJDK, for example, the jdk8u202-b08/jre/lib/security/cacerts file is used.
  • For a JDK 17 provided by OpenJDK, for example, the jdk-17.0.1+12/lib/security/cacerts file is used.

Usually mail servers use certificates signed by well known certificate authorities who's whose Root CA Certificate is Certificates are included in distributions of OpenSSL and Java.

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Recommended E-Mail Settings

Typically, no settings are required as the mail server's Root CA Certificate can be assumed to be in place.

Should verification of the mail server certificate fail, for example in the case of selfPrivate CA-signed certificates, then users can:

• copy the certificate displayed with above output to their clipboard and paste it to a file,
• import the certificate to the JOC Cockpit truststore, see JS7 - JOC Cockpit HTTPS Connections.

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The JOC Cockpit, when acting as a client, and the mail server, have to identify a common SSL protocol version:

• JOC Cockpit: The protocol version is determined by the Java version and by the java.security file in place:
  
  • An older Java version, 1.8 for example, can allow TLSv1 and TLSv1.1 SSL protocol versions that which are considered outdated or insecure with the jdk8u202-b08/jre/lib/security/java.security file:
    • jdk.tls.disabledAlgorithms=MD5, SSLv3, DSA, RSA keySize < 2048
      
      • TLSv1 and TLSv1.1 protocol versions are not disabled.
    • jdk.tls.disabledAlgorithms=SSLv3, TLSv1, TLSv1.1, RC4, DES, MD5withRSA, DH keySize < 1024, \
    EC keySize < 224, 3DES_EDE_CBC, anon
      
      • A larger number of SSL protocol versions are disabled.
  • A newer Java version, 17 for example, can disable SSL protocol versions that are considered outdated or insecure with the jdk-11.0.12+7/conf/security/java.security file.
    • jdk.tls.disabledAlgorithms=SSLv3, TLSv1, TLSv1.1, RC4, DES, MD5withRSA, \
    DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL, \
    include jdk.disabled.namedCurves
  • It is common practice that the Java versions available in an organization include adjusted copies of the java.security file that limit the use of SSL protocol versions.
• Mail Server: For compatibility reasons they mail servers tend to support outdated or insecure protocol versions for a longer time.
  • There is not a simple way to determine all protocol versions supported by a mail server. Typically this requires SSL debugging, : see Logging. The SSL debug log states the list of protocol versions offered by the client and by the mail server. If in doubt, then your system administrator should know the mail server's supported protocol versions.

...

A frequent problem is the requirement that the mail server and client should negotiate the protocol version. This does not work perfectly work for a number of mail servers, particularly not for Microsoft Exchange® servers.

Users should therefore specify a single protocol version to be used. The above chapter  Check Certificates section above explains the commands that help to determine the SSL protocol version supported by the mail server.

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Wrong use or mismatch of ciphers is not a frequent issue in mail server connections. However, if users have consider the following explanation if there is a good reason to assume mismatch of ciphers then consider the following explanation.:

For handshake in SSL connections, the JOC Cockpit, when acting as a client, and the mail server require a common protocol version (see step 3) and a common cipher.

• The SSL protocol version in use determines available ciphers.
• The same ciphers have to be in place with the Java version used by the JOC Cockpit and with the mail server.
  • JOC Cockpit: Ciphers are determined by the Java version and the java.security file in place:
    • Older Java versions, for example 1.8, tend to allow ciphers that are considered outdated or insecure. If no recent updates to Java have been applied then newer ciphers might not be available.
    • Newer Java versions, for example 17, tend to disallow a number of ciphers that are considered outdated or insecure. 
  • Mail Server: There is not a simple way to determine all the ciphers available with a mail server. Typically this requires SSL debugging, : see Logging. The SSL debug log states the list of ciphers offered by the client and by the mail server.
  • Cipher mismatch is a possible source of error - for example in the following situations:
    • An older Java version 1.8 (not recently updated) is used to connect to a mail server that is up-to-date when it comes to use of secure ciphers.
      • The mail server denies use of outdated ciphers offered by Java. The Java does not know of newer ciphers offered by the mail server.
    • A newer Java version 17 is used to connect to a mail server that is operated with older ciphers.
      • The Java denies use of outdated ciphers offered by the mail server. The mail server does not know of newer ciphers offered by Java.

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Mail servers can be configured to require authentication. Your system administrator provides will provide this information.

To verify the credentials users Users can setup an e-mail client to verify credentials and check that credentials work.

Recommended E-Mail Settings

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work.

Recommended E-Mail Settings

OAuth2 Authentication E-Mail Settings

OAuth2 authentication with mail servers allows to use an access token instead of a password:

• Display feature availability
  StartingFromRelease 2.5.2

• For earlier versions of JS7 see the section Workaround of the following change for instructions how to update to a newer version of JavaMail that allows OAuth2 authentication:
  

  Jira
  server SOS JIRA columnIds issuekey,summary,issuetype,created,updated,duedate,assignee,reporter,priority,status,resolution columns key,summary,type,created,updated,due,assignee,reporter,priority,status,resolution serverId 6dc67751-9d67-34cd-985b-194a8cdc9602 key JOC-1456

The following settings can be used:

Anchor
logging logging

Logging

When sending mail then error Error messages are raised by the JOC Cockpit JS7 - Monitor Service when sending mail. They can be found in the service-monitor.log file, see JS7 - Log Files and Locations.

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