huge mail going throw my mail server how to protect

[Ed Greshko]

On 04/06/2012 03:28 PM, Rafiqul Islam wrote:
> My question is too many unknown user sending mail using my MTA(Postfix) so that
> hotmail,google reject mail from my domain(mail.navigation.com
> <http://mail.navigation.com> and IP:202.53.168.75)  and i don't know how to stop
> this unexpected outgoing mail.

You may want to use an online tool to check your server....

http://www.mxtoolbox.com/diagnostic.aspx

http://www.mailradar.com/openrelay/

are two....