Slow license server response on Linux guest

[xhello]

Hi,
I'm aware that following description may not be sufficient to diagnose problem, but maybe someone already observed similar behavior.
My configuration is Windows 7 host and Ubuntu 12.04 guest. I'm using compiler with floating node license, so it connects to license server whenever used. I have this compiler installed on both host and guest and both versions connect to same lic-server. When compiling something on Windows response from lic-server is instant, compilation takes no more than 1 second. When compiling same file on Ubuntu, response from servers takes about 10 seconds. I wonder, why that happens? I've tried to change network adapter from NAT to bridged, but nothing changed.
Maybe it's anti-virus? I'm using McAfee, unfortunately I'm not able to disable it and check if anything changes. However, I observed such response delay just recently and before that my configuration was exactly the same.
Any ideas how to fix that, or at least how to diagnose root cause?
Thanks in advance.

[noteirak]

The guest networking config would be the first thing to check - if you didn't set it up properly, it might have issues for preleminary commuication (ARP lookup, DNS lookup, etc).
Also check ressource usage (RAM starvation in the guest? amount of CPU compared to the host? etc)
You also would do some packet sniffing to see what is going on the link and to/from where, if you didn't find anything so far.

All these are not limited to Virtualbox but to any computer you would use.

[xhello]

Guest's network configuration is fine I think. When I ping license server I get immediate response. Also HW resources are sufficient: 2 Intel cores and 4 GB of RAM designated just for guest. My rough guess is that ip packets with certain kind of information which is license request, are blocked at some level. Is it possible that e.g. host's anit-virus treats such network traffic coming from guest differently than same request to server from host?

[noteirak]

Do you get the same ping answering time as on the host? You shouldn't get more than 1 or 2 ms extra from the guest, if you get more, then something is up.
Also, the adapater you configured for the VM can have impact, did you try all of them, virtio included?
Finally, if all is fine except for the speed, did you try to do a speed time from your host and your guest from the same source, see if you get any difference? iperf could give you answers there, with different TCP window & buffer size.
Antivirus & Firewalls can impact yes, but no way to tell exactly how they interect and their impact so always best to disable all of them while testing this kind of thing.

[Martin]

If you give 4GB RAM and 2 CPUs to the guest, what are the available hardware resources of the host?

[xhello]

@noteirak:
I don't observe significant network bandwidth loss in comparison to host. It's like only requesting license somehow works slower. That's why i suspect that in this case some packets may be lost and request needs to be repeated a few times.

@Martin:
For host I have remaining 6 cores and 12 GB, so hw resources are not the issue here.

I hoped that same problem has already been observed, seems like it's not the case. Once again - my suspect is anti-virus but I can't disable to verify. The only option now is some deep measurement with wireshark, maybe this way I will find something.
Thanks, regards.