The Mail Reader Sampler should allow the specification of a port. Right now it just uses the default port for POP3 and IMAP, however obviously that is not always sufficient. The JMeter code uses Java Mail Store.connect method specifying host, username, password; but the method also has an overloaded method that allows a port to be specified. This is an easy UI fix as well and could be modeled after the HTTP Request which does offer the port specification.
Fixed: URL: http://svn.apache.org/viewvc?rev=882697&view=rev Log: Bug 47947 - Mail Reader Sampler should allow port to be overridden
This issue has been migrated to GitHub: https://github.com/apache/jmeter/issues/2295