Malformed ping requests sent using NAT

[Erik Haukjaer Andersen]

Using VirtualBox 1.5.2 installed with Windows XP SP 2. VirtualBox set up to use NAT. Due to other problems I tried to ping my nameserver from Win XP in VirtualBox (to see if there was routing through the NAT). I got no answer back in Win XP (Request timed out) Using wireshark to capture the packets I saw that the ping packets seem to have multiple problems:

• They do not use ICMP, but UDP port 7 (echo)
• The checksum is not correct

(the response is a ICMP package with Port Unreachable - because the NS server does not listen on UDP port 7)

Both linux ping and Windows XP's own ping uses ICMP ping/echo requests and not UDP echo.

[Erik Haukjaer Andersen]

WireShark dump of VirtualBox ping from Window XP (request and response)

[Erik Haukjaer Andersen]

linux ping (request and response)

[Erik Haukjaer Andersen]

Windows XP ping request (not comming from Virtual Box)

[Klaus Espenlaub]

You can attach as much proof of ping not working as you want - it is a known issue and documented in the manual. If you have an idea how to fix the issue it's very welcome.

The VirtualBox NAT engine is a purely user level implementation using the normal Unix socket interface. Sending/receiving any ping packet requires root privileges, which would prevent normal users running VirtualBox.