UDP is a lot more complex than the other types because we're moving "up" one level in the network chain. With TCP, we're using part of the underlying protocol to elicit replies (the TCP SYN/ACK sequence). With UDP, this doesn't exist - instead, we have to rely on the server on the other end to send back a reply of some kind. In your case, you're asking about port 53, which is DNS. What size of DNS packet is valid to send to your server and expect a reply back? How large of a packet is a valid packet? (I use that question because you're asking about large UDP buffers).

We've not put this in the agent at this point just because of the configuration issues involved with sending all the appropriate information to the agent. In PingPlotter, we have packet format files that describe what we will send and what to expect back from the server we're polling. These format files can be user-defined, or they can be configured in PingPlotter. Passing all this information to the remote agent starts to get pretty hard to configure, and we start to get a smaller and smaller set of users that can figure it out and that will benefit.

That's not saying it's impossible to do, just explaining some of the reasons why it's not there yet. In particular, if you just want a "port unreachable" reply back, it gets easier (if you're going to a server that will send back a "port unreachable" reply when you send to an invalid port - this is what unix-style traceroute relies on).

Have you tried using a regular instance of PingPlotter to do this test (rather than using the remote agent)? Are you entirely certain that your network would even allow this type of request (UDP port 53, large packet)? Please install PingPlotter Standard or Pro on your remote agent machine and do some adhoc testing of ports/sizes/parameters to make sure that you're getting the results you want using the UDP packets in PingPlotter. If so, we'll see if we can come up with a solution for getting the remote agent to work.

The URL parameters for the agent aren't going to be "too" helpful for your goal. Here they are, though:

User-controlled parameters:

"PacketType" - possible values "UDP", "TCP", "ExternalCom", "ICMP", "ICMPRaw", "Default".

"TCPPort" - for TCP packet type only, what port should be used.

The following values are sent from PingPlotter automatically based on parameters set:

"IP" - the IP address to target.

"UniqueID" - internal use only. Used for matching and troubleshooting purposes.

"TimeoutTime" - how long to wait for a reply in Milliseconds.

"ThreadHitDelay" - how long to wait between packets.

"PacketSize" - how many bytes in the packet.

"ToSByte" - The value to fill into the ToS/DHCP field of the outgoing packets.

"StartingHop" - What's the first hop we should query?