List of Frequently Asked Questions
Can I use a virtual machine setup (e.g. Zen or VMware)?
Using a virtual machine to perform the simulation will work in most cases. However the scheduling of your virtual machine setup may result in an inaccurate timing. Functions like delay or traffic shaping which depend on timing may not work correct. Its strongly recommended to test your setup (e.g. with netperf and ping) for verification. For a tutorial how to setup a virtual machine please have a look here: Howto: setup VMware for Wanulator
How can I simulate a modem/DSL/etc. connection?
As you may have noticed at the moment shaping of traffic is only possible on the outgoing data stream (up-stream) of an interface. To shape in both directions you need to have 2 Interface cards available (using either routed or switched mode) and apply a traffic shaping function on both interfaces up-stream.
How is the traffic shaping working?
The shaping is done by a standard token bucket shaper.
I found a bug – what shall I do?
Please report to us using the Contact page.
If I assign a function to an interface which packets will be affected?
Every function is applied to the packets of the outgoing data stream on the interface it is assigned to.
The Hardware I have seems to be not not supported (e.g. boot problems) – what now?
This may happen as its hard to keep up with the pace of new HW and new drivers being released. There are 2 possible ways to handle this: You can try to tweak the boot params (e.g. to disable hotplugging) – please have a look into the appropriate documentation for a comprehensive list of possibilities. If this doesn’t help you can run the Wanulator within a Virtual machine which should allways run fine even on the latest HW. In any case I would highly appreciate if you could send me a short notice which HW you found problematic.
Why is Wanulator only available as a live CD?
One important criteria for the Wanulator was to generate an easy to use, “out of the box experience”. A live CD solves problems like Linux kernel dependencies or environment dependencies effectively. Furthermore test software like Wanulator is expected not to be used on a day per day basis. A live CD can easily turn any available PC into a temporary test-station within seconds.
Hi, First I would like to congratulate you on making this test tool.
I wanted to know if it is possible to disable / enable DNS and UDP using this tool. I want to see how my client device behaves when i disable DNS. Thanking you in advance.
Kind Regards
Annie
Hello Annie,
you can use a drop function and apply it to every packet. In the filter setting of the function you can limit the drop to UDP or DNS (both exist in the standard filter list).
I hope that will do the job for you.
Kind regards,
Michael
Hi,
what does the Offset Parameter in the w2filterdefs.xml mean? Can i filter ip adresses with another Offset value?
And somehow the Scramblefunction doesn’t work. I edit, select every packet or something else, click Ok but the its still marked as off and therefore it doesnt scramble!?
regards
Hi Fari,
first of all thanks for reporting the scramble problem there was a bug in the settings dialog. I just uploaded a version which should fix this.
The offset parameter is the position for comparing the “content” within the received packet. For filtering an IP address this should be 26 for the source and 30 for the destination address – if I am not mistaken. This is assuming a commonly used ethernet2/DIX header with just 2 byte type field behind the addresses (no tagged header with vlan, snap or similar).
Kind regards, Michael
>open a xterm and edit the w2filterdefs.xml file you find in the /root directory.
So can I write filter directly in this file? Any documentation?
What I need is drop RCT TCP packets (may in with some probability). Is it possible?
Thanks.
Hi,
yes you can edit the file directly (you need to restart WANulator afterwards). Currently I have no documentation – but if you have a look into the file you will find it quite abvious – yust have a closer look to the given examples. I am not sure what you mean by RCT / TCP packets? Could you give a pointer to the protocol or spec?
Kind regards,
Michael
Is it possible to manipulate only RTP Packets?
Hi, unfortunately you cannot filter RTP directly (at least not with a static filter used in WANulator). So you have two options:
Use the UDP filter (in case you have no other UDP traffic which you want to exclude from manipulation)
Or you need to know the port number the traffic is destinated to (or sourced from) – which may be a problem if the port is dynamicaly chosen.
In that case you can add a filter by closing WANulator, open a xterm and edit the w2filterdefs.xml file you find in the /root directory.
E.g. the offset should be 36 and the content the hex value of your destination port…
UDP isn’t an option, because there is other UDP traffic that I want to exclude from manipulation.
So i added a filter called RTP with an offset of 36 and a hex port value of 0bb8 (3000).
But sadly the filter does not manipulate any packet.
I want to analyse the reaction of VOIP calls to packet loss. So I sent RTP data from one client to another and vice versa. Destination port of client A is 3000 and of Client B it is 3001.
I tried it with both as hex port value.
Any idea, why this doesn’t work?
(Syntax is like any other filter in the w2filterdefs.xml, and the RTP filter is also listed in WANulator)
Hi,
its hard to tell – could you send me a small sample record of the packets (with wireshark or tcpdump -n …) and the filtersetting so I could try to reproduce it here?
Kind regards,
Michael
Is it possible to define custom bandwidth settings? eg 256Kbit/s etc.
Hi,
you can just edit the limit speed field to any bandwidth setting by clicking into it.
Kind regards,
Michael