Re: Is it possible to use Iperf behind a NAT?
I blieve the Rich Carlson of ANL has a server that does what you are
looking for:
http://miranda.ctd.anl.gov:7123/
This is a Web100 based server that runs Iperf tests and provides an
anlysis of path.
Thanks!
--Reddy
From: SMTP%"jdugan --at-- ncsa.uiuc.edu" "Jon Dugan" 20-DEC-2002 22:47:57.65
To: dspisak --at-- nonmundane.org
CC: iperf-users --at-- dast.nlanr.net
Subj: Re: Is it possible to use Iperf behind a NAT?
On Fri, Dec 20, 2002 at 05:18:38PM -0800, Daniel Spisak wrote:
> Jon,
>
> Thanks for your reply to my questions I do appreciate them! here are
> my responses to what you wrote:
>
> > First off, I'm not quite sure what the setup is here. Do you have a
> > collection of machines that can participate in these tests or are you
> > testing from the user's brower to the server?
>
> The scenario is this is for any old random machine on our network to use, as
> a client. The server will always be the same system. Some machines will have
> directly routable IP addresses whereas other systems lie behind a router
> doing NAT, so the system has a non-routable IP address.
OK. So you're delivering an application to the users to run?
> >will do testing in both directions. That is the client will contact the
> >server and it will do a test one direction and then test the other.
> >Assuming that we use the same TCP connection for both directions, it will
> >Just Work (TM).
>
> That would be a pretty awesome feature for Iperf to have.
It's coming, but it's not here yet.
> >Iperf doesn't presently support this, but it could be added
> >easily -- if you do decide to add it please send us the patch.
>
> I know some C and some X86 asm but I've never coded a project like what
> Iperf is so I am afraid I would be at a loss at where to even begin to start
> to give Iperf NAT functionality. Basically, since my clients will live
> behind a NAT router that they are probably not comptent enough to setup port
> mappings for, nor would my tech support staff wish to have to walk an
> uninformed user through that process.
It's really not that bad. The only functionality I was suggesting was the
ability to set the port which Iperf uses to initiate it's connection when it
is a client.
> The only way I guess I could see it working is if I modified the Iperf code
> so that I could have a user behind the NAT initiate a test as a client to my
> static server, and the server records the port the Iperf client opened from.
> Then after the client to server test completes Iperf on the client side
> would spawn a server Iperf process on the old source port on the clients
> side.
This is actually what I was suggesting. There is a problem though, since
everyone is connecting to the same server to do their tests you can't spawn
a seperate Iperf to do the test because to get back through the NAT you need
to source your traffic from the same port the server was on. There is
however a way around this -- using a proxy. The proxy listens on a
particular port on the server and clients connect to it and the proxy starts
an Iperf server on another port and tells the client to test against that
port. Once the test is complete the client starts a server listening on the
port that it used as a client and then the proxy starts a client targetted
at machine behind the NAT.
> And I am not even sure if that method would work, I'm just speculating. The
> reason why I was thinking about a static file download test is that using
> Java, I could have their browser download a file from my static server, once
> that file was downloaded it would record the time it took and calculate the
> users download speed. The Java app would then have the client side browser
> upload the just downloaded file back to the server to get an upload/upstream
> throughput speed.
Yep, that would work fine. It sounds like it might be the easiest to
implement. For your application this might be the best thing. It will
allow you to have people point their web browsers at a website and get
a report. Otherwise you would need to maintain a binary for each platform
you support.
> I was just trying to see if there was a way to do this with Iperf without
> having to setup a portmapping on the users NAT router.
There is, it just requires being a bit tricky.
Good luck!
Jon
--
Jon Dugan | Senior Network Engineer, NCSA Network Research
jdugan --at-- ncsa.uiuc.edu | 269 CAB, 605 E Springfield, Champaign, IL 61820
217-244-7715 | http://www.ncsa.uiuc.edu/~jdugan/