Session timeout in liferay

We can set session timeout by two ways

1.web.xml
2.portal.properties

1.web.xml

You can find web.xml in \tomcat-7.0.42\webapps\ROOT\WEB-INF

<session-config>
<session-timeout>30</session-timeout>
 </session-config>

Change session-timeout as required.Its 30 minutes by default.

After modifying restart server.

2.portal.properties

Set
session.timeout=30

in portal-ext.properties

And also you can use 

session.timeout.warning=10

It will give warning before 10 minutes of session timeout.

session.timeout.warning=0

It won't give any warning.

session.timeout.redirect.on.expire=false

Set this to true if you need to redirect to default page after session timeout.