error in smpt.gmail.com host

[kib_tse]

I've been testing some code for sending secure e-mail, and I've been using my Gmail account for testing.
but when I run it i am getting this
DEBUG SMTP: trying to connect to host "smtp.gmail.com", port 465, isSSL false
Unknown SMTP host: smtp.gmail.com;

so please help me.

[Norm]

How? Could you post the related code and the args that are causing the error.

[fishtoprecords]

I've been testing some code for sending secure e-mail, and I've been using my Gmail account for testing.
but when I run it i am getting this
DEBUG SMTP: trying to connect to host "smtp.gmail.com", port 465, isSSL false
Unknown SMTP host: smtp.gmail.com;

so please help me.

First, have you used dig or nslookup to verify that your computer can properly resolve smtp.gmail.com to a proper IP address?

That is the problem resulting in the "unknown host" error

Then check that you really want port 465 instead of the standard 25.

Then check your firewall, since its unusual to have 465 open

[kib_tse]

That is good help. but how can i check whether my computer is resolving stmp.gmail.com or not

[fishtoprecords]

I told you how in my prior response:

First, have you used dig or nslookup to verify that your computer can properly resolve smtp.gmail.com to a proper IP address?

"dig" and "nslookup" are programs.
Run them

[kib_tse]

thank you but
I am not familiar with dig and nslookup.
but istead i wrote a code that take the hostname as an input and give host address as a result.
I have run the code like this
D:/> Enter host name: smtp.gmail.com
Ip address is 64.233.179.109

what is this? is my computer resolving or not?

[fishtoprecords]

I am not familiar with dig and nslookup.

The first rule of programming is to be able to know where the bugs are. If you are writing networking code, you will calling code to do things like resolve names, open ports, etc.

In order to know if your code is working or not, the easiest thing to do is use a known working utility that does parts of the same thing.

learn to use nslookup and dig
learn to use telnet
learn to use telnet with various port numbers

[kib_tse]

i have run this code :
package javaapplication14;
import java.io.*;
import java.net.InetAddress;
import java.util.Properties;
import java.util.Date;

import javax.mail.*;
import javax.mail.internet.*;


/**
*
* @author project
*/
public class SendMail {

public static void main(String[] argv) throws Exception{

String host = "smtp.gmail.com";
String from = "kibtse@gmail.com";
String to = "kib_tse@gmail.com";

// Get system properties
Properties props = System.getProperties();

// Setup mail server
props.put("mail.smtp.host", host);
props.put("mail.smtp.starttls.enable", "true");
props.put("mail.smtp.auth", "true");

// Get session
Authenticator auth = new MyAuthenticator();
Session session = Session.getDefaultInstance(props, auth);

// Define message
MimeMessage message = new MimeMessage(session);
message.setFrom(new InternetAddress(from));
message.addRecipient(Message.RecipientType.TO,
new InternetAddress(to));
message.setSubject("Hello ");
message.setText("Welcome to gmail");

// Send message
Transport.send(message);
}
}

class MyAuthenticator extends Authenticator
{
MyAuthenticator() { super(); }

protected PasswordAuthentication getPasswordAuthentication()
{ return new PasswordAuthentication("kibtse", "pwd"); }
}
and i have included mail.jar and activation.jar. but i am geting this error
Exception in thread "main" javax.mail.MessagingException: Can't send command to SMTP host;
nested exception is:
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path validation failed: java.security.cert.CertPathValidatorException: timestamp check failed
at com.sun.mail.smtp.SMTPTransport.sendCommand(Unknow n Source)
at com.sun.mail.smtp.SMTPTransport.sendCommand(Unknow n Source)

please help me

[Niveditha]

Why dont you try with other hosts like gmail-smtp.l.google.com or gmail-smtp-in.l.google.comans check if you are getting the same error?

[Niveditha]

sorry it was "gmail-smtp-in.l.google.com and "

[kib_tse]

I tried with "gmail-smtp-in.l.google.com" i am getting the same error
like:
Exception in thread "main" javax.mail.MessagingException: Unknown SMTP host: gma
il-smtp-in.l.google.com ;
nested exception is:
java.net.UnknownHostException: gmail-smtp-in.l.google.com
at com.sun.mail.smtp.SMTPTransport.openServer(Unknown Source)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(Un known Source)
at javax.mail.Service.connect(Unknown Source)
at javax.mail.Service.connect(Unknown Source)
at javax.mail.Service.connect(Unknown Source)
at com.sun.mail.smtp.SMTPTransport.connect(Unknown Source)
at javax.mail.Transport.send0(Unknown Source)
at javax.mail.Transport.send(Unknown Source)
at SendMail.main(SendMail.java:38)
what is the problem?

[fishtoprecords]

what do you get running dig or nslookup?

[kib_tse]

thank you !!! now it is working.

[extempore]

Kindly add the following line of code in your property file

props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
props.put("mail.smtp.socketFactory.fallback", "false");

[atripavan]

i was getting the same error too..
try this one..it should work..this worked for me..
"gmail-smtp-msa.l.google.com"

[jetinder20]

hi,
even i tried same thing and getting same exception i.e java.net.UnknownHostException: smtp.gmail.com

and when i ran nslookup

>nslookup gmail.com
Server: UnKnown
Address: fec0:0:0:ffff::1

*** UnKnown can't find gmail.com: No response from server
this is the response i m getting...
please help me resolve the issue..

regards