[Mimedefang] Adding support for learning our addresses

[Matthew.van.Eerde at hbinc.com]

Mark Damrose wrote:
>> -----Original Message-----
>> From: Philip Prindeville
> 
>> On the other hand, if, like me, your local address *is*
>> unroutable, then it means that you're behind a firewall, and
>> need to do a gethostbyname() on your own name to figure out
>> what your outside address is (i.e. what the address of your
>> firewall is that proxies for you).
> 
> That wouldn't work on my system, and many others.  If you do a
> gethostbyname() you'll get the local unroutable address back -
> since the internal and external DNS for my namespace are maintained
> on separate servers.

Hence services like www.whatismyip.com

What I think would be really nice is a new kind of DNS record... something like WHOAMI... that provides this kind of a service.  So for example

dig -t WHOAMI your-friendly-neighborhood-dns-server.example.com

would return (in the ANSWER section) the IP address that your-friendly-neighborhood-dns-server sees the request coming from.

So if I'm on a 10. intranet cloud, and the DNS server is too, then I'll get back my 10. IP address.
Or if I ask a DNS server on the other end of an 192.168. IP-mapped VPN connection, I'll get back the 192.168. IP address it was mapped to.
Or if I ask my ISP's server on the internet (but beyond my firewall) I'll get my firewall's routable IP address.

-- 
Matthew.van.Eerde (at) hbinc.com               805.964.4554 x902
Hispanic Business Inc./HireDiversity.com       Software Engineer