+config TFTP_PORT
+ bool "Set TFTP UDP source/destination ports via the environment"
+ help
+ If this is defined, the environment variable tftpsrcp is used to
+ supply the TFTP UDP source port value. If tftpsrcp isn't defined,
+ the normal pseudo-random port number generator is used.
+
+ Also, the environment variable tftpdstp is used to supply the TFTP
+ UDP destination port value. If tftpdstp isn't defined, the normal
+ port 69 is used.
+
+ The purpose for tftpsrcp is to allow a TFTP server to blindly start
+ the TFTP transfer using the pre-configured target IP address and UDP
+ port. This has the effect of "punching through" the (Windows XP)
+ firewall, allowing the remainder of the TFTP transfer to proceed
+ normally. A better solution is to properly configure the firewall,
+ but sometimes that is not allowed.
+