HTTP is a property in the portal.properties file, which is the default configuration file for Sun GlassFish Web Space Server. You can override this property using portal-ext.properties file.
See system.properties for more HTTP settings.
Set the maximum number of connections.
#com.liferay.portal.util.HttpImpl.max.connections.per.host=2 #com.liferay.portal.util.HttpImpl.max.total.connections=20  | 
Set the proxy authentication type.
#com.liferay.portal.util.HttpImpl.proxy.auth.type=username-password #com.liferay.portal.util.HttpImpl.proxy.auth.type=ntlm  | 
Set user name and password used for HTTP proxy authentication.
#com.liferay.portal.util.HttpImpl.proxy.username= #com.liferay.portal.util.HttpImpl.proxy.password=  | 
Set additional properties for NTLM authentication.
#com.liferay.portal.util.HttpImpl.proxy.ntlm.domain= #com.liferay.portal.util.HttpImpl.proxy.ntlm.host=  | 
Set the connection timeout when fetching HTTP content.
com.liferay.portal.util.HttpImpl.timeout=10000  |