nmap in Virtualbox weirdness

Hi All,

The setup:
Host: Ubuntu 12.04 / 12.10
Virtualbox Guest: Ubuntu 12.04 / 12.10

The issue:

From the guest OS, running nmap with anything greater than T2, the NIC
becomes 'stuck' a simultaneous ping of a local box will start
reporting 'Destination host unreachable'
If the nmap scan is set above T3 the NIC freeze is almost
instantaneous. Killing the nmap process returns the NIC to normal
behaviour within approximately 30 seconds.
Under Virtualbox the NIC can be set to NAT or bridged, it makes no difference.
This occurred under both guest OSes and hosts running different
versions of nmap. This makes me think it's not an nmap issue but
Oracle forums have not brought forward any help.

Any thoughts gratefully received.

Boggy

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