Solaris does something similar as do SGI nowdays - its a big win to do so,
and 4000 user ports isnt enough.
> IPPOR_USERRESERVED. This can also screw with firewalls and packet
> filters which assume normal clients only use port numbers in the
> 1024-5000 range.
Your packet filter is badly set up if its using ports for tcp client/server
filtering not SYN|!ACK
Alan