In this example we will block MSN (Hotmail) and Yahoo mail but will allow users to access on google mail.
Please go to Objects Settings>>Keyword Object
and add the ff profiles.
Go to Keyword Object>>Keyword Group then create a group ex. Blacklist Mail.
Select the webmails to be blocked then click OK.
Go to CSM>>URL Filter Profile and create the ff groups as shown in this example.
Create a profile to allow access to Gmail
Click edit on the URL Access Control then select the keyword object Google Mail.
Create a profile to block webmail
Select the keyword group “Black list Mail”.
Go to CSM>>Web Content Filter Profile
Create a profile “Block Webmail”, tick on enable and webmail.
Go to Firewall>>General Setup, select “Block Webmail” on the drop down menu for Web Content Filter
Then click OK to save.