Following table lists five message types in TFTP.
|Messsage Opcode||Message Type||Description|
|1||RRQ (Read Request)||The TFTP RRQ (Read Request) message type is used by the client to establish a TFTP connection for reading file from the server.|
|2||WRQ (Write Request)||The TFTP WRQ (Write Request) message type is used by the client to establish a TFTP connection for writting file to the server.|
|3||DATA||The TFTP DATA message is a block of data.|
|4||ACK (Acknowledgment)||The TFTP ACK (Acknowledgment) message type is used to acknowledge the receipt of a data block.|
|5||ERROR||The TFTP ERROR message type is used to notify a problem during data transmission or when a TFTP connection cannot be established.|