Tag Archives: server

Accessing localhost from virtual machine or Android Emulator

Two problems- one solution i.e. 10.0.2.2

Sometime back, I faced an issue that I had installed a virtual machine on mu linux machine. I had a server/ website running which I wanted to access from virtual machine. http://localhost/site simply refused to work. A little googling helped with an answer to use http://10.0.2.2/site

Again faced similar issue. Was trying to access local website from within android emulator. Again localhost refused to work. And guess who was the rescuer? yep 10.0.2.2 again ūüôā

Adding/ Removing Browser Authentication for tomcat app

There can be many cases in your projects where you would like to add a browser authentication for your project. But there will be a few where you will actually need to remove that. That’s what happen to me today. Checked out code for a project and tried to run on local tomcat instance,¬†everything¬†worked fine. When tried to open up the app like localhost:8080/myapp, browser asked for username and password. I had no idea about username and password.

So started by googling about removing browser authentication in tomcat, that was a mistake. Could not find a single site talking about removal of authentication. After spending 20 minutes, I got the idea to actually look for- how to set the browser authentication. And bam- that worked.

In your apps web.xml, there will be setting for <security-constraint> where you can set up the <login-config> as basic (or actually remove in my case).

<!–
Define the Members-only area, by defining
a “Security Constraint” on this Application, and
mapping it to the subdirectory (URL) that we want
to restrict.
–>
<security-constraint>
<web-resource-collection>
<web-resource-name>
Entire Application
</web-resource-name>
<url-pattern>/members/*</url-pattern>
</web-resource-collection>
<auth-constraint>
<role-name>member</role-name>
</auth-constraint>
</security-constraint>
<!– Define the Login Configuration for this Application –>
<login-config>
<auth-method>BASIC</auth-method>
<realm-name>My Club Members-only Area</realm-name>
</login-config>

Source point 5 of  http://oreilly.com/java/archive/tomcat-tips.html

Restricting recipient emails in postfix

Had a requirement today to restrict emails from our postfix server to only to some specific domains/ email addresses. It turned out to be pretty simple

At the end of /etc/postfix/main.cf just add

smtpd_recipient_restrictions =
   check_recipient_access hash:/etc/postfix/access
   permit_auth_destination
   reject

and at the end of /etc/postfix/access add the domain names/ email addresses which can accept emails

kamalmeet.com OK
abcd@gmail.com OK

Now update postfix db

postmap hash:/etc/postfix/access

and finally restart service

service postfix restart

That’s it