DNS reverse lookup

[.]

Hope this helps:

InetAddress.getByName returns a InetAddress object so something like this
may work:

java.net.InetAddress ipNumInetAddress =
ava.net.InetAddress.getByName( "192.122.98.61" );
java.lang.String hostName = ipNumInetAddress.getHostName();

....also note that InetAddress.getByName() is a static method.



"Joseph S D Yao" <jsdy at cospo.osis.gov> wrote in message
news:20000516185459.C10003 at washington.cospo.osis.gov...
> On Tue, May 16, 2000 at 12:23:38PM -0500, Martin wrote:
> ...
> > 1/ Is it possible to do a reverse DNS in Java code.
>
> Yes.  Turing rule.
>
> > 2/ I have tried the following code, and it does not work -
>
> This code seems odd to me.  This may just be because I do not yet know
> Java.  ;-)
>
> > InetAddress r;
>
> Could you tell us the quick specs for the InetAddress methods
> getByName(), getByAddr(), and getHostName()?
>
> >            r = InetAddress.getByName("192.122.98.61");
>
> In Java, can you call a method by reference off of the class name,
> instead of off an object of the class?  Is this really the function to
> convert a string with a dotted-quad representation of an IP address
> into the 32-bit InetAddress representation?  It seems to me that you
> would want to be saying:
>
> r = InetAddress("192.122.98.61");
>
> but that may just be the C++/ECL constructor functions in my brain
> speaking.
>
> >            s = r.getHostName();
>
> This is where I would think getByAddr() might be used ... but it might
> return an array of strings, instead of a single string.  If it follows
> the C library model.
>
> > 3/ If it is not possible, how else can I do it?. I have tried to
> > use Windows NT's  -
> > nslookup <ipaddress>.in-addr.arpa
>
> This would not work, anyway.  You need to REVERSE the IP address.
> nslookup 61.98.122.192.in-addr.arpa
> or, if it behaves like Unix 'nslookup', just say:
> nslookup 192.122.98.61
> and it will do all the rest.  A fact that annoys some.  ;-)
>
> > and this doesn't work either! Has this anything to do with the
> > fact that I am behind a firewall??
>
> Possibly.  But it is quite possible to resolve IP addresses from behind
> a reasonably secure firewall, if it is properly configured.  You can
> browse Internet sites, can't you?  ;-)
>
> --
> Joe Yao jsdy at cospo.osis.gov - Joseph S. D. Yao
> COSPO/OSIS Computer Support EMT-B
> -----------------------------------------------------------------------
> This message is not an official statement of COSPO policies.
>
>
>