Traffic generator for loadbalancer test

John Hall j.hall at
Thu May 10 20:43:37 UTC 2001

Several possibilities below:

http_load ( is a good tool,
although it takes some liberties that can in some cases make it
not-at-all representative of real-life performance.  It's HTTPS
support is especially non-representative, because it does not
shortcut an ACK resend problem in the SSL protocol that almost all
web clients do shortcut, causing a .2 second delay in every transaction.
If you have enough clients (say 50), the delay per connection is
small enough to disregard.

For arbitrary protocols, we've found that Perl's Net::RawIP
( to be surprisingly efficient.  You still
need lots of clients, but it's easy to code a distributed benchmarking
tool in Perl with it.

Get the source for a WHOIS and wrap a for loop around the send() call. (  Sends
requests with spoofed source addresses.  BE CAREFUL!!! If you're not
on an isolated network, the responses to the spoofed requests can leak
out of your network, causing hate mail, bandwidth throttling, embarrassment,
and possibly camel toe!

The DoS section of PacketStorm ( can
be a great source of benchmarking tools!

Good luck.


Arnold Nipper wrote:
> I am looking for a traffic generator for stresstesting load balancers. Has
> anyone an idea if there is software or anything else? I'm particularly
> interested in testtraffic for DOMAIN and WHOIS.
> Thanks, Arnold
> --
> Arnold Nipper / nIPper consulting          mailto:arnold at
> Heilbronner Str. 34b                       Phone:  +49 700 NIPPER DE
> D-76131 Karlsruhe                          Mobile: +49 172 2650958
> Germany                                    Fax:    +49 180 505255469743

John Hall <jhall at>                                      F5 Networks, Inc.
BIG-IP Test Manager                                           206-272-5555

"But what we need to know is, do people want nasally-insertable computers?"

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