Configure server firewall request/response

Hi
I use a .net ODBC connection and the connection to Pgsql db is though a firewall that only allow request and a answer
tothe response. 

I some times get Error from the client

"The connection has been disabled. ---> System.Data.Odbc.OdbcException: ERROR [08S01] No response from the backend;"

I check the firewall logs and it seems like some responses get blocked in the firewall could this be slow response or
somekind of keep alive response. 
Are there some settings to make the Pgsql db server to work better with a firewall request/response the KeepAlive is
turnedoff. 

regards
Lars