Solaris Sendmail – Troubleshooting


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7 Responses

  1. Hasan Khalil says:

    Let me clarify our email architecture for our system email alerts.

    All unix/linux machines sendmail client is set to use two MTA relay sendmail servers internally in our network.

    Then those two MTA relay sendmail servers forwards all the email to our company’s microsoft exchange server (Microsoft servers are managed and administered by a seperate windows team).

    Then mircosoft exchange server delivers the system alerts to valid microsoft exchange email IDs, e.g.

    So basically of all the client machines has the IP address of internal network MTA relay sendmail server and MTA sendmail relay server has the IP of Microsoft exchange server for D{MTAHost} in

    All the system email alerts configured by us and different application/database team (in their scripts) is properly being delivered.

    Now the problem we are facing is this. Along with all the system alerts emails, all of the sendmail client machines are also sending out native OS users system generated emails (to the native user ) as well. And …… our internal network MTA relay sendmail server obviously also relay them to our domain’s microsoft exchange server, which obviously cannot recognize the destination address (e.g. floods our outbound email gateway (sendmail server) with all those unwanted emails and overwhelms the mail queue.

    So far, we concluded to use ‘.forward’ option to at least deliver all the emails to proper email address ( of the respective owner team of the unix/linux system user. That way our corporate outbound sendmail email gateway will not be brought down due to 100,000+ unwanted system users email everyday.

    Another option we have read somewhere is to configure /etc/mail/access file on the internal MTA relay sendmail server, which would discard or reject any email addressed to But we are not sure about the syntax to be used. Whether we can use wild card options to reject/discard all emails addressed to or we have to add lines for each and every user of all the servers.

  2. Ramdev says:

    Hi Hasan, I understood what you are saying.  

    Configuring .forward file to redirect mails to the respective server owners sounds like an idea, but I am  concerned about the fact that you need to touch the sendmail configuration  everytime you have to add the servers in the network. That is not an ideal practice to do, and can make sendmail vulnerable for human mistakes.

    The other alternative, configuring /etc/mail/access is something I  would prefer to test as a solution. Because that will require one time configuration for the setup. you just need to Relay the specific domain name  and rest will be declined by default.

    I am just wondering what is bind and Os version you are using?

  3. Hasan Khalil says:

    Hi Ramdev, sendmail clients are mix of Solaris 10, Solaris 9, RHEL. Whereas internal MTA relay server is configured on primary internal DNS server which is Solaris 9 update 7.

  4. Hasan Khalil says:

    Or, our issue can also be resolved if cron emails are stopped. I have posted regarding to cron at

  5. Ramdev says:

    what is the Bind version?

  6. Hasan Khalil says:

    sendmail client running on Solaris 10 update 10 is “BIND 9.6-ESV-R5-P1”. sendmail MTA server on Solaris 9 update 7 has “BIND 8.3.3”.

  1. October 6, 2015

    […] Read – Basic Troubleshooting […]

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