On 09/16/2013 04:25 PM, Alan Bateman wrote:
On 16/09/2013 15:00, Paul Sandoz wrote:
Hi Peter,
Nice observation about name resolving.
On my MacBook, if i switch off the wifi, then 7 addresses are
returned 4 for the en0 and 3 for lo0. Seems overkill to use all of
them and the sub-interefaces, if any. I agree with Doug, selecting
the first interface's MAC address is probably sufficient.
We periodically come across environments where they are a lot (as in
hundreds) of network interfaces configured and might indeed be
overkill to use bits from all of them.
On getHardwareAddress then there are platforms where you need to be
root or have special privileges to get the mac address so this is one
reason why it might return null. I see Doug's patch handles this and
I'm just mentioning in that it may not be source of bits in some
environments.
For the security manager case there is a permission check to avoid
leaking details about the environment to untrusted code. So to be
useful when running with a security manager will require it to be done
as a privileged action.
-Alan.
Hi,
So perhaps the right strategy would be to get the hardware address of
the 1st interface that has it, but don't bother to search more than N
interfaces (if 1st N interfaces don't return HW address then it is a
good chance that OS security does not allow accessing them). Testing at
least 2 interfaces would allow to skip over loopback in environments
where it is returned as 1st interface. Other kinds of interfaces that
don't have hardware address are some Point-to-Point interfaces (VPN
interfaces for example).
Peter
