Reverse DNS and IDENT Protocols
If there is a problem in which users can connect to servers but have to wait a long before data comes back, something might be preventing the server from doing reverse DNS or IDENTD. To work around the DNS issue, be sure to allow UDP/53 to the DNS server from the destination server, provided the DNS server is behind the CBAC router. To get around the problem for IDENT protocol, be sure to allow TCP/113 through the CBAC router so that the server can communicate with the client on TCP/113.