Mail services checking - URGENT

[David Southwell]

Hi

I have had a series of attacks on a system which resulted in a hijack of our 
mail system.

I believe I have now fixed the main problem but I need a tool that will 
reliably, and independently of the mail logs check my network for all 
outgoing mails and hold them up until I am certain that there all loopholes 
have been closed.

Can anyone please let me have some recomendations on the best way of going 
about this

Thanks

David