[PLUG] UDP packet level testing

[Keith Lofstrom]

I want to test for dropped UDP packets between two specific machines
over the internet.  I have root access to both machines.  I would
like to be able to control the destination port, packet size, etc. 
Burst testing would be nice but not mandatory.  What I DON'T want
to do is throw data at a kernel buffer or socket or whatever, and
let the kernel choose the packet size.

Are there any good tools for this?  I've tried nttcp, but that is
stream oriented, and seems to let the kernel choose packet sizes. 
iperf is an elaboration of nttcp, and nettest is a wrapper around
iperf.  Too high level, not enough instrumentation.

What this is all about is that I am told that my Actiontec cable
router to Verizon FIOS truncates UDP packets to 512 bytes.   I
would like to test that before I ask Verizon to switch me over
to direct Cat5 connection (ditching the feature-laden but poorly
implemented Actiontec).

BTW, is there any way to set the mtu (maximum package size) that
an interface/protocol will use FOR UDP ONLY, without hacking the
kernel or restricting TCP and other protocols?  I will want to
do this as a further test.  I know I can do "ifconfig eth1 mtu 500"
on the interface, to limit all packet sizes, but I would like to
try it on UDP only.

Keith

-- 
Keith Lofstrom          keithl at keithl.com         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs