UDP port mapping disappears from a host outer interface

[TriAnMan]

I have a Windows 7 host with CentOS 7 guest with "--hpet on" and a NAT network interface. Guest has a DHCP server (bind9) which I want to use in my network. So I have a port forwarding configured like this: ​http://screencast.com/t/815d9MGK3

When I start my guest box everything is ok: I see a listening port and nslookup resolves names.

C:\>netstat -a -b -n

Active Connections

  Proto  Local Address          Foreign Address        State
  TCP    0.0.0.0:53             0.0.0.0:0              LISTENING
 [VBoxHeadless.exe]
  TCP    0.0.0.0:80             0.0.0.0:0              LISTENING
 [VBoxHeadless.exe]

....

  UDP    0.0.0.0:53             *:*
 [VBoxHeadless.exe]

....

But in a couple of minutes (5-15) UDP mapping disappears. There is no any related error message in the VBox.log or VBoxStartup.log. nslookup doesn't resolve names. Netstat shows no UDP port opened.

If I try to delete and add a UDP mapping on this running box I receive an error: ​http://screencast.com/t/RTywcC6GPA or an error about memory can't be readed. and a guest box goes into an aborted state.

This behavior doesn't depend on Windows Firewall state. I have no antiviruses running but has the Avast installed.

I have just found more reproducible behavior.

Box setup is the same.

Start a guest-box.

On the host use:

nslookup example.com 192.168.1.151

and then

nslookop example.com 127.0.0.1

after that if I use

nslookup example.com 192.168.1.151
DNS request timed out.
    timeout was 2 seconds.
Server:  UnKnown
Address:  192.168.1.151
DNS request timed out.
    timeout was 2 seconds.

but

nslookop example.com 127.0.0.1

still working and

C:\>netstat -a -b -n

Active Connections

  Proto  Local Address          Foreign Address        State
  TCP    0.0.0.0:53             0.0.0.0:0              LISTENING
 [VBoxHeadless.exe]
  TCP    0.0.0.0:80             0.0.0.0:0              LISTENING
 [VBoxHeadless.exe]

....

  UDP    0.0.0.0:53             *:*
 [VBoxHeadless.exe]

....

seems to be ok. In this case sometimes I can delete and add a UDP mapping for 53 port and nslookup example.com 192.168.1.151 becomes working again. Or sometimes settings window for a guest-box isn't appearing. P.S.: 192.168.1.151 is my host LAN interface.

[Valery Ushakov]

Is that still a problem. It sounds like a duplicate of #13475.

[Valery Ushakov]

I did some testing and I'm pretty sure this is a different manifestation of #13475.