Block External Email

[1onerobertone1]

Hello -

Basically I would like to start blocking external email access from the internal network such as Yahoo Mail.  I don't want to block access to Yahoo itself, just inbound email from Yahoo and other sites like that.

Is there any documentation on how to best accomplish this?

Thanks in advance!

[AnalysisMan]

You may block the Yahoo email server's domains. 

Incoming Mail (POP) Server: pop.mail.yahoo.com

Outgoing Mail (SMTP) Server: smtp.mail.yahoo.com

However, it works only for direct access from the internal client to the servers. Many users use web browsers to access their emails (webmail).

Plus, there is another issue that the users may access the Yahoo emails through other email providers. (e.g., I access my Yahoo emails via Gmail - there is a feature called 'Import mail' or 'Check mail from other accounts.')

That means you have to block other service providers such as Google.

[1onerobertone1]

@AnalysisMan Thank you for your reply!

"Many users use web browsers to access their emails (webmail)."

That is exactly what I'd like to prevent.  Is that possible with the palo's?

[AnalysisMan]

You may block webmail domains like mail.yahoo.com, mail.google.com.
Or
If you have the URL Filtering license, you can block entire web-based emails with a category called 'web-based-email.'

[AnalysisMan · Accepted solution]

There is another way to block the email applications. You can block the application with 'gmail-base', 'yahoo-mail-base.'