Category: Howto

How do I troubleshoot outbound email on Linux?

Check which MTA is being used

First, determine which mail transfer agent (MTA) you are using. Currently, Eclipse Linux servers are configured using the postfix MTA. If you are running an older system, you may be using the sendmail MTA. To determine which MTA you are running, use the following command:

ls -l /etc/alternatives/mta

If the command returns a link to “/usr/sbin/sendmail.postfix”, your system is configure to use postfix. If it returns a link to “/usr/sbin/sendmail.sendmail”, your system is configured to use sendmail.

Check the SMTP relay server

Next, verify that your system is pointing to the correct SMTP relay server.

For systems using postfix, the command is:

grep ^relayhost /etc/postfix/main.cf

For systems using sendmail, the command is:

grep ^DS /etc/mail/sendmail.cf

Check the mail logs

Once you have confirmed that the MTA is relaying to the correct SMTP server, the next step is to check the email service logs. To view the last 10 log messages and monitor the file, run:

tail -f /var/log/maillog

Check the mail queue

Once you have checked the mail logs, the next step is to check the mail queue for pending and differed email messages.

mailq

Tell Postfix to process the queue now

postqueue -f

Delete all queued mail

postsuper -d ALL

Send a test message from the command line

To send a test message from the Linux command line, use the following command (replace email@domain.com with your email address):

echo test | mail email@domain.com

If you don’t receive your email, check the logs (see above) for error messages.

Send a test message from Eclipse

In a separate Eterm or Solar window, try sending an email. If you don’t receive the message, check the logs (see above). Make note of any error messages, such as “relay denied” or “cannot connect to SMTP server.” These messages are the best source for determining which element in the email service architecture is incorrect. In our experience, most issues are related to incorrectly configured SMTP relay servers, or SMTP servers that do not allow relay from the Eclipse server.

Dell Firmware Update

There are a few different methods for updating your Dell server’s firmware, but we’ll walk you through the simplest and most reliable method that uses the server’s “Lifecycle Controller” which is also known as the “Unified Server Configurator”.

This method can be used with any operating system (i.e. Linux, Windows, VMware, etc.), because it operates outside of the OS, similar to the BIOS menus. It requires a working network connection with Internet access and rebooting the server for as long as it takes for the updates to be downloaded and installed, which is typically 15 minutes to an hour, depending on the speed of your Internet connection and how many updates need to be installed.

Here is a step-by-step guide:

  • Before rebooting the server, make note of the server’s LAN IP address, network mask, and default gateway, because you’ll need to enter these settings into the Lifecycle Controller the first time you use it.
  • Reboot the server.
  • When the BIOS menu and Dell logo appears, press the <F10> key within 10 seconds
  • Wait for the Lifecycle Controller GUI to appear
  • If this is your first time using the Lifecycle Controller to access the Internet and install updates, you’ll need to configure the network interface:
    • Click Settings in the left pane
    • Select Network Settings
    • Select Static IP address
    • Specify the IP Address, Subnet Mask, Gateway and DNS server you previously noted
    • Click Finish
  • Click Platform Update in the left pane
  • Click Launch Platform Update in the right pane
  • Select FTP Server
  • Verify that the server name is ftp.dell.com
  • Click Next
  • The Platform Update tool will now download a list of available packages for your server. This may take a while, depending on the speed of your network connection.
  • When prompted, review and select the appropriate updates to be installed
  • Click Apply
  • The system will reboot after the update process is complete. When applying more than one update, the system may need to reboot between updates. In this case, the system boots directly into USC and continues the update process. No action on your part is required when the system reboots to complete the update process.
  • When the updates are complete, the system will boot back into your operating system.

For more information, please see Updating the Platform on Dell’s website.

How do I access Dell OpenManage?

The Dell OpenManage Server Administrator allows system administrators to manage individual servers from an integrated, Web browser-based graphical user interface (GUI). OMSA is designed for system administrators to manage systems locally and remotely on a network.

You may access the Dell OpenManage web interface from any computer (replace 192.168.1.100 with your server’s LAN IP address):

  • Launch the OpenManage web interface (https://192.168.1.100:1311/)
  • Log in using your root username and password

What type of tasks can be performed using OMSA?

  • View the server’s hardware configuration
  • Check for hardware errors
  • Check for firmware updates
  • Replace or reconfigure storage

Resources:

How do I monitor Linux system performance using top?

The top program provides a dynamic, real-time view of the actual process activity on a server. By default, it displays the most CPU-intensive tasks running on the server and updates the list every five seconds.

Commonly Used Hot Keys

The top command provides several useful hot keys:

Hot Key Usage
c Display full command-line arguments for each process. Useful for identifying specific phantoms and java processes.
m Displays memory information off and on.
A Sorts the display by top consumers of various system resources. Useful for quick identification of performance-hungry tasks on a system.
o Enables you to interactively select the ordering within top.
k Issues kill command.

Resources:

How do I remove a Linux Eterm user via the GUI?

Warning: As always, please exercise caution when performing system maintenance, especially when initiating processes that can potentially delete data.

To remove a Linux Eterm user using the GUI:

  • System -> Administration -> Users and Groups
  • Select the user from the list
  • Select the Delete button
  • Verify that the dialog box says “I won’t delete username’s home directory (‘/u2/eclipse’)” before selecting Yes to proceed

Warning: if prompted to remove the shared home directory as shown in the dialog box below, uncheck the box before clicking Yes. Failure to do so will result in the removal of the entire Eclipse database directory (/u2/eclipse).

For your convenience, here is a screencast that covers the entire process for locking or removing a user:

If you prefer to use the command line, please see this page for instructions.