gm writes:If you have your own mail server and any DNS issue, you can go to www.dnsreport.com to test your domain name.
I found out that my server (FC1) has been blacklisted by some sites. I was wondering if there's a way to determine why it's been blacklist.
Yes, there is. All known public blacklist sites provide an explanation, usually at the URL given in the bounce message, or indirectly via their web site, after you submit your IP address.
All you have to do give yourself sufficient motivation to go and investigate the situation by yourself, instead of sitting back and waiting for someone to work Miss Cleo's crystal ball, and figure out what your problem is, without you providing a single bit of useful information, such as what your actual IP address is.
think it's because there mite be an open relay in my server. I was wondering if there's a way to test for this on my server? In general I was wondering how to test the security of my network on the whole in case there are other leaks on the network.
Your first step is, again, to obtain the reason for the alleged blacklisting. Once you've determined what the reason is, you'll be on your way to investigating the nature of the problem.