If req-filename and real-filename values are set and valid, the requested filename will be replaced with matched file. Requested filename as regular expression (regex) if field is left empty it defaults to. This is used to enable large downloads using TFTP server. If set to yes TFTP server will allow sequence number to roll over when maximum value is reached. Range of IP addresses accepted as clients if empty 0.0.0.0/0 will be used

To add new tftp access rule you will have to issue command add under /ip tftp menu with attributes as follows: How many times this access rule entry has been used (read-only) This menu only shows 1 additional attribute compared to what you can set when creating rule, see explanations of attribute descriptions lower. If in this menu are no rules, TFTP server is not started when RouterOS boots. This menu contains all TFTP access rules. That has to be set specifically for TFTP rule that allows it.

Note: Since RouterOS 5.6 sequence number roll-over is supported by TFTP server.

Configure tftp server