The TFTP ERROR packet is used to notify a problem during data transmission or when a TFTP connection cannot be established. The format of TFTP ERROR packet is as shown below.
Following are the fields of TFTP DATA packet.
- Opcode : Opcode field of TFTP ERROR packet is 16-bits (2-bytes) in length. TFTP ERROR packets have an opcode value of "5".
- Error Code : The error code of TFTP ERROR packet is an integer showing the type of the error. Following table lists the possible values of error code of TFTP ERROR packet.
- Error Message : Error Message field of the TFTP ERROR packet is a variable size field. Error Message field is a human readable field and is in ASCII.
- All 0s : The TFTP ERROR packet is terminated with one byte of all zeros.
|File not found
|Disk full or Quota exceeded
|Illegal TFTP operation
|Unknown port number
|No such user
Following image shows a Wireshark packet capture screeshot of TFTP ERROR packet.