WhatsUp Gold - How to check that a TFTP server is running

Question/Problem: How do I check that a TFTP server is running?

Answer/Solution: Add the following service definition to your library of services to check for the presence of a TFTP server.

Note that there is no status check query for TFTP, so you just need to get a predictable response back from the server -- to do this, ask for a file you know doesn't exist and check that the correct error code is returned.

The definition for a TFTP service check would look like this, assuming your TFTP server returns the standard string "File not found" and does not have the requested file called "nosuchfile.txt". You may need to tweak this depending on your actual TFTP server's implementation response. (See RFC1350 for other standard error strings and error codes if interested.)

Name: TFTP (Trivial File Transfer Protocol)
Type: TCP/IP Service Check
UDP
Port 69
Timeout of 5 seconds
Script:
Send=%000%001nosuchfile.txt%000octet%000
Expect=%000%005%000%001File not found%000

Note that TFTP uses zero as the initial byte in the response.

The definition in your services.ini file becomes
[TFTP (Trivial File Transfer Protocol)]
CLSID={72B6D231-D71E-11d2-8F74-0040054D7C1D}
Lines=2
Line000=Send=%000%001nosuchfile.txt%000octet%000
Line001=Expect=%000%005%000%001File not found%000
TYPE=1
PORT=69
TIMEOUT=5