The client is infected with a virus and immediately sends a warning email.

Hello Jacky Tu,

Please have a look at this article regarding Email Alerts setup 

Regards,

I set it up like this but didn't send an instant alert email.

My vendor tell me all clients must open SMTP port, client will send an alert email.

Hello Jacky Tu,

Just to clarify, you tested the settings (per previous kb) and everything seemed fine, but still no alerts are being received? 
Can you try running an Eicar test to see if it triggers an email alert? 

Also, can you provide more information regarding what is your vendor suggesting?  
Have you tried their suggestion on one computer to see if it alleviates the issue? 

Regards,

I tried it the way the manufacturer suggested.  can send an alert email.

If I have 1000 clients, I have to set up all the clients? this is no smart.

Hello Jacky Tu,

Could you please clarify what vendor/settings are you changing?
Any additional details that you could provide will also be appreciated, including repro steps and/or environment details. 

Regards,

My company has set internal mail relay,  I added that client in mail relay, Can send alert mail.

I can't added all client in mail relay , because this violates the information security policy.

So my question is that Can it send an alert email from the console? instead of issuing an alert message from the client.

Hello Jacky Tu,

To set up Email Alerts from the console (based on dashboard thresholds) please follow this article:

How to set up Enterprise Console email alerts based on dashboard thresholds

Regards,