Remote host replies to SYN+FIN
nightrecon at verizon.net
Thu Aug 7 22:38:59 UTC 2008
kalin m wrote:
> does anybody have any idea how to resolve this?
Not without a lot more information. But I may be able to fathom some wild
guess, generically speaking.
Only allow connections to set up like this:
pass out quick on $ExtIF inet proto tcp all flags S/SA keep state
pass in quick on $ExtIF inet proto tcp from any to any port 48080 flags S/SA
Notice I included the "keep state" for illustrative purposes. With the
latest version of pf this is now the default condition and including it is
no longer required.
Then either block the SYN+FIN before they reach these rules, or simply allow
it to fall through to a generic dumping rule like this:
block in quick log on $ExtIF all
This way the SYN+FIN doesn't match the rules for legitimate traffic
and "falls through" to default block all "non-legitimate" traffic.
YMMV - Mike
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