Allow to force TFTP to use a fixed UDP port

(Add a configuration option CONFIG_TFTP_PORT and optional env variable tftpport)
Patch by Jerry Van Baren, 10 Jan 2005

1 files changed, 19 insertions, 0 deletions

diff --git a/README b/README
index e3d053717c..3b36e50e11 100644
--- a/README
+++ b/README
@@ -1487,6 +1487,22 @@ The following options need to be configured:
 		When SystemACE support is added, the "ace" device type
 		becomes available to the fat commands, i.e. fatls.
 
+- TFTP Fixed UDP Port:
+		CONFIG_TFTP_PORT
+
+		If this is defined, the environment variable tftpport
+		is used to supply the TFTP UDP source port value.
+		If tftpport isn't defined, the normal pseudo-random port
+		number generator is used.
+
+		The purpose for this 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.
+
 - Show boot progress:
 		CONFIG_SHOW_BOOT_PROGRESS
 
@@ -2452,6 +2468,9 @@ Some configuration options can be set using Environment Variables:
 		  Useful on scripts which control the retry operation
 		  themselves.
 
+  tftpport	- If this is set, the value is used for TFTP's
+		  UDP source port.
+
    vlan		- When set to a value < 4095 the traffic over
 		  ethernet is encapsulated/received over 802.1q
 		  VLAN tagged frames.