Chapter 10 Install and System Administration for FortiOS 5.0 : Session helpers : DNS session helpers (dns-tcp and dns-udp)
  
DNS session helpers (dns-tcp and dns-udp)
FortiOS includes two DNS session helpers, dns-tcp, a session helper for DNS over TCP, and dns-udp, a session helper for DNS over UDP.
To accept DNS sessions you must add a security policy with service set to any or to the DNS pre-defined service (which listens on TCP and UDP ports 53). The dns-udp session helper also listens on UDP port 53. By default the dns-tcp session helper is disabled. If needed you can use the following command to enable the dns-tcp session helper to listen for DNS sessions on TCP port 53:
config system session-helper
edit 0
set name dns-tcp
set port 53
set protocol 6
end
See Also
• Viewing the session helper configuration
• Changing the session helper configuration
• DCE-RPC session helper (dcerpc)
• File transfer protocol (FTP) session helper (ftp)
• H.245 session helpers (h245I and h245O)
• H.323 and RAS session helpers (h323 and ras)
• Media Gateway Controller Protocol (MGCP) session helper (mgcp)
• ONC-RPC portmapper session helper (pmap)
• PPTP session helper for PPTP traffic (pptp)
• Remote shell session helper (rsh)
• Real-Time Streaming Protocol (RTSP) session helper (rtsp)
• Session Initiation Protocol (SIP) session helper (sip)
• Trivial File Transfer Protocol (TFTP) session helper (tftp)
• Oracle TNS listener session helper (tns)