How can I prevent all instant messaging clients on my network while still allowing our proprietary im/email system to function? We are using a sonicwall and barracuda web filter 300.
We have been compromised and one email account is internally sending out a lot of spam. We shut it down and another machine popped up infected and doing the same thing. How can we scan all out bound emails for spam just like incoming email? We use a barracuda 300 spam firewall.