The udp state engine is used for UDP services. It allows one or more responses to a UDP request. The requests are validated to make sure they come from the correct address and port and are sent to the correct address and port. The response source address and port checking can be modified using the parameters below.
The discriminator for the udp state engine is the port number of the UDP service.
The udp state engine has the following parameters:
Response timeout in seconds - Specifies the amount of time to wait for UDP responses. -1 specifies an infinite response timeout. (Default = 60 seconds).
Number of responses per request - Specifies the number of expected responses for each request. If the number of response specified is 0, any number of responses can be received and the session terminates only after an idle period when no responses have been received. Never specify both a response time of -1 and 0 for the number of responses per request.
Flag value - Specifies valid sources for UDP responses.
If bit 0x01 is set, the UDP response can come from a different host than the request, which is useful for UDP services on multihomed servers that respond using a different address.
If bit 0x02 is set, the UDP response can come from a different port than the request.
If both bit 0x02 and bit 0x04 are set, then requests can come from a different port than the request, and subsequent requests can also use that new port. This is useful for handling TFTP servers that sometimes switch ports in mid-session.