VMware
4 Replies Last post: Apr 17, 2009 2:15 AM by AWo  

NAT guest on Vista host, firewall is blocking relevant traffic posted: May 16, 2007 10:52 PM

Click to view maxxess's profile Novice 17 posts since
Jul 20, 2006
Sorry if this has already been covered. Please point me to a whitepaper/faq/or forum topic if this problem has already be solved. (I am running current RTM of Vmw Wks6)

Problem:
When running NAT guests under host Vista x64, windows firewall blocks traffic to guest. Bridged guests work just fine.

Example:
Guest-xp can not ping anything in NAT-mode since all ICMP-replies are dropped by Vista firewall. If guest is bridged all works fine. I have read other topics where vpn-users have serious problems when running NAT on guest with a Vista host.

Dropping ICMP (in my case) may seem like a small problem, but a guest that is member of a domain in Active Directory will (at least in my setup) not get the latest policies, no loginscripts will be run etc etc due to firewall blocking in host(!). Much traffic from DC:s in AD will be dropped by Vista firewall when destination is a guest with NAT (except ICMP UDP is also dropped)

Adding a firewall rule on host which allows ICMP from all IP:s solves most problems (my guest get correct policy and can map sambashare as homedrive via login script).

Either VMw6 should seamlessly integrate with the firewall when running NAT or there should be a white paper/faq on how to configure host. I can not find one or the other.

The answer to my question might be RTFM which I have not done for v6. I will happily read such material if the answer lies therin.

Reproduce the problem:
Install a windows guest on Vista (x64) host which has firewall enabled, use NAT for guest.
-> You can not ping anything from guest

Switch to bridged network for guest.
-> Ping works fine

Switch to NAT and add firewall rule in Vista host to allow ICMP.
-> Ping works fine

(ping is just an example of ICMP that Vista blocks for guests)

Since NAT does not work "out of the box" when running Vista as a host I would expect a whitepaper or at least a FAQ but I get nada on my searches?

Click to view jeffreyvsmith's profile Lurker 3 posts since
Oct 12, 2006
This is exactly what I have been struggling with. New to Vista and having trouble figuring out the firewall stuff. How did you configure the ICMP rules? Did you use the Windows Firewall with Advanced Security?

Edit: Tried to create a icmp v4 rule in Advanced Security. Alowed in/out, etc. and now my guest can ping into my 10.0.1.0/24 network from the NAT 192.168.241.0/24 subnet. But, I still cannot ping my host IP 10.0.1.15/24. ?

Message was edited by:
jeffreyvsmith
Click to view AWo's profile Champion vExpert 4,493 posts since
Nov 27, 2003
I only can guess, but under Windows XP you can deactivate the Windows firewall only (or completely :-) ) from VMnet8 which is by default the NAT device. Shouldn't this do it?

AWo
Click to view dcoli9's profile Lurker 1 posts since
Apr 16, 2009
I had the same problem with a Vista 64 Business host using VMware Server 2.5, and running XP in a VM. I found two things:
  1. You can disable the firewall on the host machine by going to the Advanced tab and just disabling it for the VMWare8 network adapter. Then enable the firewall on your VM.
  2. I have to restart my NAT service periodically using vmnetcfg.exe NAT tab. It may be every time I restart the VM. Not sure why.
Colin
Click to view AWo's profile Champion vExpert 4,493 posts since
Nov 27, 2003
Have you already tried to set the VMnet connection on the host to private? To public connections restrictions apply.

Read this on how to achieve this: http://technet.microsoft.com/en-us/library/bb727037.aspx


If you found this information useful, please consider awarding points for "Correct" or "Helpful" replies. Thanks!!

AWo
VCP / vEXPERT 2009

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