So, I have started to use fail2ban with shorewall.  It looks like the
correct mechanism to use is shorewall drop along with BLACKLISTNEWONLY=No.

The problem is that that ends up blocking the inbound traffic from
locally generated outbound sessions.

My goal here is to add a drop/blacklist rule, dynamically, when fail2ban
detects a host is doing bad things.  A portscan is a good example to use
for "bad things".  But I also want to block/drop any established
"inbound" connections that are open, for example to shut down a
brute-force attacking of SSH that might have started before the portscan
started.

The collateral damage here though is for example, IRC servers that I
want to connect to that want to do a portscan of me to make sure I'm not
an open relay.  They end up blacklisted in the dynamic chain with no
regard to whether the packets it's dropping are from outbound
connections or inbound.

Maybe the problem is that I'm wanting to have my cake and eat it too
since there is no concept of inbound/outbound with ESTABLISHED sessions.

Thoughts?

b.

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