Could not connect to SMTP host localhost port 25 nested exception is java net ConnectException Connection refused connect

Question

I m doing application for send email from localhost in jsp  amp  i found error like Could not connect to SMTP host  localhost  port  25  nested exception is  java net ConnectException  Connection refused  connect plz check and give me solution or idea if you have  for that i m using below code    Thanking you in advance     lt    page language  java  import  javax naming   java io   javax mail    javax mail internet   com sun mail smtp     gt    lt html gt   lt head gt   lt title gt Mail lt  title gt   lt  head gt    lt body gt    lt   try    Session mailSession   Session getInstance System getProperties        Transport transport   new SMTPTransport mailSession new URLName  localhost        transport connect  localhost  25 null null       MimeMessage m   new MimeMessage mailSession      m setFrom new InternetAddress   gt  lt  request getParameter  from    gt  lt         Address   toAddr   new InternetAddress                   new InternetAddress   gt  lt  request getParameter  to    gt  lt                     m setRecipients javax mail Message RecipientType TO  toAddr       m setSubject   gt  lt  request getParameter  subject    gt  lt        m setSentDate new java util Date        m setContent   gt  lt  request getParameter  description    gt  lt     text plain       transport sendMessage m m getAllRecipients        transport close       out println  Thanks for sending mail       catch Exception e      out println e getMessage       e printStackTrace        gt     lt  body gt    lt  html gt

User · Answer

First you have to ensure that there is a SMTP server listening on port 25.

To look whether you have the service, you can try using TELNET client, such as:

C:\> telnet localhost 25

(telnet client by default is disabled on most recent versions of Windows, you have to add/enable the Windows component from Control Panel. In Linux/UNIX usually telnet client is there by default.

$ telnet localhost 25

If it waits for long then time out, that means you don't have the required SMTP service. If successfully connected you enter something and able to type something, the service is there.

If you don't have the service, you can use these:

A mock SMTP server that will mimic the behavior of actual SMTP server, as you are using Java, it is natural to suggest Dumbster fake SMTP server. This even can be made to work within JUnit tests (with setup/tear down/validation), or independently run as separate process for integration test.
If your host is Windows, you can try installing Mercury email server (also comes with WAMPP package from Apache Friends) on your local before running above code.
If your host is Linux or UNIX, try to enable the mail service such as Postfix,
Another full blown SMTP server in Java, such as Apache James mail server.

If you are sure that you already have the service, may be the SMTP requires additional security credentials. If you can tell me what SMTP server listening on port 25 I may be able to tell you more.

User · Answer

The mail server on CentOS 6 and other IPv6 capable server platforms may be bound to IPv6 localhost    1  instead of IPv4 localhost  127 0 0 1    Typical symptoms    root host     telnet 127 0 0 1 25 Trying 127 0 0 1    telnet  connect to address 127 0 0 1  Connection refused   root host     telnet localhost 25 Trying   1    Connected to localhost  Escape character is       220 host ESMTP Exim 4 72 Wed  14 Aug 2013 17 02 52  0100   root host     netstat -plant   grep 25 tcp        0      0    25                                                   LISTEN      1082 exim              If this happens  make sure that you don t have two entries for localhost in  etc hosts with different IP addresses  like this  bad  example    root host     cat  etc hosts 127 0 0 1 localhost localdomain localhost localhost4 localdomain4 localhost4   1       localhost localhost localdomain localhost6 localhost6 localdomain6   To avoid confusion  make sure you only have one entry for localhost  preferably an IPv4 address  like this    root host     cat  etc hosts 127 0 0 1 localhost  localhost localdomain   localhost4 localdomain4 localhost4   1       localhost6 localhost6 localdomain6

[email] Could not connect to SMTP host: localhost, port: 25; nested exception is: java.net.ConnectException: Connection refused: connect

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