com.sun.mail.util.DNS.save Maven / Gradle / Ivy
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package com.sun.mail.util;
import java.net.*;
import java.io.*;
import java.util.*;
import java.util.logging.Level;
import javax.naming.*;
import javax.naming.directory.*;
/**
* DNS support utility methods.
*
* See also http://www.rgagnon.com/javadetails/java-0452.html.
*
* @author Bill Shannon
*/
public class DNS {
private static MailLogger logger = new MailLogger(
DNS.class,
"DNS",
"DEBUG DNS",
PropUtil.getBooleanSystemProperty("mail.dns.debug", false),
System.out);
// No one should instantiate this class.
private DNS() {
}
/**
* Return a list of mail servers for the domain from DNS MX records.
*/
public static List getMailServers(String domainName)
throws NamingException {
Hashtable env = new Hashtable();
env.put("java.naming.factory.initial",
"com.sun.jndi.dns.DnsContextFactory");
DirContext idc = new InitialDirContext(env);
Attributes attrs = idc.getAttributes(domainName, new String[] { "MX" });
Attribute attr = attrs.get("MX");
List res = new ArrayList();
if (attr != null && attr.size() > 0) {
NamingEnumeration en = attr.getAll();
// XXX - should sort by priority/weight
while (en.hasMore()) {
String x = (String)en.next();
System.out.println("GOT MX: " + x);
String f[] = x.split(" ");
if (f.length > 1 && f[1].endsWith("."))
f[1] = f[1].substring(0, (f[1].length() - 1));
res.add(f[1]);
}
} else {
// if we don't have an MX record, try the machine itself
// XXX - why should we do this?
attrs = idc.getAttributes(domainName, new String[] { "A" });
attr = attrs.get("A");
if (attr == null)
throw new NamingException("No match for name '" + domainName + "'");
NamingEnumeration en = attr.getAll();
while (en.hasMore()) {
String x = (String)en.next();
System.out.println("GOT A: " + x);
if (x.endsWith("."))
x = x.substring(0, (x.length() - 1));
res.add(x);
}
}
return res;
}
// Can also look for NS records to see if domain exists:
/**
* Return a list of name services for the domain from DNS NS records.
*/
public static List getNameServers(String domainName)
throws NamingException {
Hashtable env = new Hashtable();
env.put("java.naming.factory.initial",
"com.sun.jndi.dns.DnsContextFactory");
DirContext idc = new InitialDirContext(env);
Attributes attrs = idc.getAttributes(domainName, new String[] { "NS" });
Attribute attr = attrs.get("NS");
List res = new ArrayList();
NamingEnumeration en = attr.getAll();
while (en.hasMore()) {
String x = (String)en.next();
System.out.println("GOT NS: " + x);
if (x.endsWith("."))
x = x.substring(0, (x.length() - 1));
res.add(x);
}
return res;
}
public static void main(String[] argv) throws Exception {
List res;
System.out.println("MX");
res = DNS.getMailServers(argv[0]);
for (String s : res)
System.out.println(s);
System.out.println("NS");
res = DNS.getNameServers(argv[0]);
for (String s : res)
System.out.println(s);
}
}