2.1 Transport
The Kerberos V5 protocol uses UDP and TCP for transport ([RFC4120] section 7.2). KILE uses UDP by default; however, if the message size exceeds a specific configurable value (message size threshold), TCP SHOULD<3> be used. The threshold applies to AS and TGS messages. They do not apply to AP exchange messages because the transport is controlled by the application protocol.
KILE MUST have a working DNS infrastructure. KILE SHOULD NOT use the Internet Protocol (IP) addresses of the KDCs. DC SRV records registration is defined in [MS-ADTS] section 6.3.2.3.