Data Domain: How to Troubleshoot Mail Server Issues | SMTP

Troubleshooting Mail Server Issues on Dell Data Domain: Step-by-Step Guide

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Follow these steps when troubleshooting mail server issues on Dell Data Domain:

1. Verify Mail Server Configuration:

# config show mailserver

If not configured, set the mail server.

# config set mailserver <host>

In DD OS 7.0+, additional support is added for the SMTP encryption method STARTTLS.

If the mail server is 365 or another mail server that uses STARTTLS, then run the configuration command again with port and username.

Configure the mail server again with either port 25 or 587 with the customers username.

If no password is needed for the mail server, press enter after running the command.

Sometimes no password is required but best to check with the email administrator. 

The SMTP server requires that the authenticated user either be the admin email account or have permission to send on behalf of it. If the authenticated user is not authorized, the server rejects the email.

If you run the config set mailserver command and authenticate with Tony@Avenger.com, then Tony@Avenger.com must also be configured as the admin-email user or have explicit permission to send on behalf of that admin email. Otherwise, the SMTP server rejects the request. 

To check the admin-email username run the following command.

# config show admin-email

If you are not sure about the admin-email username, check with your email administrator and check your other data domains.

To configure the mail server again with either port 25 or 587 with customers username. 

# config set mailserver smtp.example.com port 587 user username

Or

# config set mailserver smtp.example.com port 25 user username

Example:

sysadmin@DD6900 config set mailserver smtp.dell.com port 25 user john.doe@dell.com
Enter the password for the Mail (SMTP) server:
The Mail (SMTP) server is: smtp.dell.com
The Mail server username is:
sysadmin@DD6900-2#

To test autosupport, use the following commands.
 

# autosupport send <yourEmailAddress@company.com> cmd "net show settings" 

# autosupport test email yourEmailAddress@dell.com
# autosupport test alert-summary

2. Network Connectivity Checks:

• Check if you can ping the mail server hostname or IP address.

# net ping mailserver
# net ping x.x.x.x

# net show settings

# net ping mailserver interface ethXx
# net ping x.x.x.x interface ethXx

# net ping mailserver interface ethMa

• If you like a specific interface to use with the mail server, you can setup a static route.

# net route add host <IP or hostname of mailserver> gw <IP of your local gateway for the NIC you want to leave> dev [interface]

# net route add host DellMail.com gw 1.2.3.4 dev eth3a

To display the gateways on the DD.

# net route show gateway

Example

tester64@R2D2 net route show gateway
IPv4 Default Gateways
gateway IP     source
------------   -----------------
1.2.3.4        interface
------------   -----------------

3. DNS Resolution:

• Check if DNS is configured, and test to resolve a name that should be resolvable.

# net show dns
# net lookup <a resolvable name like the hostname of the DD or the mailserver>

If you must add a DNS server, use the following command:

# net set dns <IP>
# net lookup <a resolvable name like the hostname of the DD or the mailserver or even emc.com>

To add the hostname/IP to the Data Domain's hosts file for local resolving, use the following command:

# net hosts add <IP address> <host>

Example:

# net hosts add 192.168.1.1 mailrelay.company.com
# net ping <host> count 4

4. Check SMTP Ports:

• Check if the ports required are open SMTP is port 25 and sometimes 587 is used.

Contact your network firewall team to check if ports 25 and 587 are open.

Data Domain Support can access bash mode and run telnets from the data domain to your mail server.

# telnet <mailserver> 25
# telnet <mailserver> 587

Check if the mail server can be pinged.

If you know the interface on the dd that the mail server communicates with you can, run the following command from bash.

# telnet <MailserverIPOrhostname> 25 -b <ipaddressOfInterfaceOnDD>
# telnet <MailserverIPOrhostname> 587 -b <ipaddressOfInterfaceOnDD>

5. Whitelist Data Domain IPs:

• Has the data domain IP addresses been whitelisted on the mail server?

In order for traffic to be allowed out the data domain mail server IP addresses and maybe hostnames, must be whitelisted.
You must double verify if this has been done because if it is not done, it fails.
You see an error example Unable to send message: (errno 4: Cannot open socket for sending email).

To list the data domain IP addresses to provide the customer, run the following command:

You can also find the DD IPs in the Auto-Support.

# net show set

If using Microsoft 365, these links may be helpful.

• Configure anti-spam policies in EOP (External Link)
• Configure the advanced delivery policy for third-party phishing simulations and email delivery to SecOps mailboxes (External Link)

6. Firewall/NAT Rules:

• Has a NAT rule been added for outgoing traffic for data domain for SMPT mail server?

If example Palo Alto firewall is used, then a policy must be added so that DD SMTP mail server traffic can communicate outbound.

Contact your firewall team to check if traffic is allowed outbound and perform live monitoring troubleshooting to see traffic flows outbound.

An error message that is sometimes displayed when the firewall is blocking traffic is Unable to send a message: (errno 10: SMTP operation timed out)
 

7. Admin Host Configuration:

• Sometimes an admin host is required check if an admin-host is configured and check your other data domains if they have one.

# config show admin-host

Display the administrative host from which you can connect to the protection system to view system logs and use system commands.

# config set admin-host  <host>

Set the machine from which you can log in to the protection system to view system logs and use system commands.

The hostname can be a simple or fully qualified hostname or an IP address.