Back Scatter (Backscatter)

There are many situations where apparently harmless back scatter (bounces from incoming email) can cause your server to be blacklisted. To minimize the chances of this please do the following

1. Use the config checker and apply the recommended settings
2. Make sure you have g_friends_safer "true"
3. Make sure you ahve g_responder_safer "true"

In addition you should consider banning forwarding settings to problem domains, e.g.
forward_illegal to="*@gmail.com" apply="user"

This rule prevents users adding a forwarding rule to a gmail account. You might do this if gmail is seeing incoming forwarded spam from your server and blacklisting it.