DNS for Mail service.

Question

I want to use java to send mail by smtp service.
but for some hosts, the InetAddress class can't find out
the ip address for the hosts, which need the MX flag in
DNS Query data package(UDP).
I can send the query and get the result from the ISP
DSN server, but the replay UDP data is quit complex,
I have not find a simple way to get the IP address from
the UDP data.
Can any one help me? Or Are you doing the same thing
like that ? We can talk about it together.
Thanks
Scott

Answer 1

HI Duker,
I tred to use ur way.
in the following code,
an excpetion thrown .like
"javax.naming.NoInitialContextException: Cannot instantiate class: com.sun.jndi.dns.DnsContextFactory. Root exception is java.lang.ClassNotFoundException: com.sun.jndi.dns.DnsContextFactory"
And I try to find the related classes in the libs,
but can not find it,so I can not get any related document about the usage of the related classes.
Can you give me more help?
Regards.
Scott
<code>
package dnstest;
import java.util.*;
import javax.naming.*;
import javax.naming.directory.*;
public class dns_t {
public static void main(String[] args) throws NamingException{
Properties props = new Properties();
props.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.dns.DnsContextFactory");
props.put(Context.PROVIDER_URL, "dns://ns1.dns.com/thedomain.com");
DirContext ictx = new InitialDirContext(props);
Attributes attrs1 = ictx.getAttributes("www", new String[] {"A"});
Set st = attrs1.keySet();
Iterator it = st.iterator();
NamingEnumeration it=attrs1.getAll();
while (it.hasMoreElements()) {
System.out.println((String)it.nextElement());
Hi,
You could try the JNDI-DNS early access service
provider, it is basically a provider for the JDNI api
that allows you to query a given DNS server.
Checkout
http://developer.java.sun.com/developer/earlyAccess/jnd
/#DNS
The below code is a simple test that looks up the IN A
record for www.thedomain.com
import java.util.*;
import javax.naming.*;import javax.naming.directory.*;
>
public class DnsTest {
public static void main(String[] args) {
Properties props = new Properties();
props.put(Context.INITIAL_CONTEXT_FACTORY,
"com.sun.jndi.dns.DnsContextFactory");
props.put(Context.PROVIDER_URLURL, "dns://ns1.dns.com/thedomain.com");
DirContext ictx = new
x = new InitialDirContext(props);
Attributes attrs1 = ictx.getAttributes("www",
("www", new string[] {"A"});
Set st = attrs1.keySet();
Iterator it = st.iterator()
while (it.hasNext()) {
System.out.println((String)it.next());
Hope this helps
Duke Ronlund
CoreJ.com
I want to use java to send mail by smtp service.
but for some hosts, the InetAddress class can'tfind
out
the ip address for the hosts, which need the MXflag
in
DNS Query data package(UDP).
I can send the query and get the result from theISP
DSN server, but the replay UDP data is quitcomplex,
I have not find a simple way to get the IP address
from
the UDP data.
Can any one help me? Or Are you doing the samething
like that ? We can talk about it together.
Thanks
Scott