Sorry for the delay in responding as I was trying to get better idea about this from the FreeBSD world :) Comments inlined:

On Mon, Mar 12, 2012 at 12:35 AM, Laine Stump <laine@laine.org> wrote:
On 03/12/2012 01:27 AM, hiren panchasara wrote:


On Wed, Mar 7, 2012 at 9:44 AM, hiren panchasara <hiren.panchasara@gmail.com> wrote:
For dumpxml <interface>, check rc.conf (which may or may not contain <interface> related settings). Print whatever you can find regarding that interface.

for example, my rc.conf has following entry:
 
ifconfig_em0="DHCP"

What should be the o/p of "dumpxml em0" ?

Is that the only information pertaining to the configuration of the interface? If so, then it would be something like:

<interface type='ethernet' name='em0'>
  <start mode='onboot'/>
  <protocol family='ipv4'>
    <dhcp peerdns='yes'/>
  </protocol>
</interface>

I'm making the assumption here that the presence of the "ifconfig_em0" line in /etc/rc.conf implies the interface will be started when the system boots (looking back at the backups of my old NetBSD system config, it looks like that is actually controlled by the presence of the interface name in the "network_interfaces" variable, but FreeBSD may be different). I'm also making the assumption that, by default, the dhclient setup on FreeBSD accepts the DNS server info from the dhcp server and puts it into /etc/resolv.conf (that's the meaning of "peerdns='yes'").

"network_interfaces" is deprecated now. So, only way to specify boottime configuration is "ifconfig_<interface>"
 
If I am not wrong, all examples in /tests/interface/ are of "dumpxml --live".

No, exactly the opposite. All of the examples in tests/interface are the input to ncf_define() / output from ncf_if_xml_desc(), i.e. *not* the live state of the interface, but its configuration information.

Okay.

thanks,
Hiren