How to enable an SMTP logging in Veeam ONE

In some cases, it might be required to have detailed logging of this activity for troubleshooting such things as missed alarm notification, unexpected content inside the e-mail message or for other purposes.

Before performing the further steps, please make sure that you have configured SMTP server settings in Veeam ONE Monitor server settings (https://helpcenter.veeam.com/docs/one/deployment/notification_smtp_server.html).

This logging is disabled by default and must be enabled in the registry:

  1) Log on to the machine where Veeam ONE Monitor service is installed.
       Open Registry Editor and navigate to the Veeam ONE Reporter registry folder:
       For both x86bit and x64bit systems: HKEY_LOCAL_MACHINE\SOFTWARE\Veeam\Veeam ONE Monitor\Service\
   2) Create the following registry key:
       Name – LogSmtpActivity
       Type – DWORD
       Value – 1 *
   3) Restart the Veeam ONE Monitor service (VeeamDCS.exe process)

• 1 - means "enable", so if you have no necessity for the further logging of SMTP dialogs you can set it to 0 or completely remove the value.

After this action, all further SMTP activities will be reflected in the files named as "VeeamDCS-MailActivity-<YYYY_MM_DD_HH_MM_SS>.log" in folder %ProgramData%\Veeam\Veeam ONE Monitor\Logs. Each log file contains a full SMTP dialog between the SMTP server on sending individual e-mail, including the status codes (220, 250, etc.) and HTML markup of the subjected e-mail.

Each log has the following format (an example):

Connected to smtp://smtprelay.contonso.com:25/
S: 220 smtprelay.contonso.com ESMTP Postfix
C: EHLO [192.168.0.1]
S: 250-smtprelay.contonso.com
S: 250-PIPELINING
S: 250-SIZE 36700160
S: 250-ETRN
S: 250-STARTTLS
S: 250-ENHANCEDSTATUSCODES
S: 250-8BITMIME
S: 250 DSN
C: MAIL FROM:<VeeamOneServerMachine@contonso.com> SIZE=364
C: RCPT TO:<recepient@contonso.com>
S: 250 2.1.0 Ok
S: 250 2.1.5 Ok
C: DATA
S: 354 End data with <CR><LF>.<CR><LF>
C: From: VeeamOneServerMachine@contonso.com
C: Date: Tue, 11 Feb 2020 13:35:53 +0300
C: Subject: Veeam ONE Monitor
C: Message-Id: <WB128P30U9U4.IS9J8ZHC935G3@VeeamOneServerMachine>
C: To: recepient@contonso.com
C: MIME-Version: 1.0
C: Content-Type: text/html; charset=utf-8
C: Content-Id: <HNT78P30U9U4.094QYWZZHYV63@VeeamOneServerMachine>
C: 
C: This is test e-mail message sent by Veeam ONE Monitor.
C: .
S: 250 2.0.0 Ok: queued as 804B240A1D
C: QUIT
S: 221 2.0.0 Bye