The PHP-version that I am running is 4.2.2 and not 4.3.2, unfortunately I can't upgrade to reproduce the problem due to the fact that the system isn't mine.

When calling imap_open("{localhost}","user","pass"); and not specifying port number the call takes about 14-15s to complete.

This is not the issue when using a port number when calling:
imap_open("{localhost:143}","user","pass");

This last call takes about 1 sec (in my case) to complete, and it is not due to network instability. I have seen the same problem described in the documentation about imap-support in php.

PHP-version is 4.2.2
php-imap: $Id: php_imap.h,v 1.17.2.1 2002/03/11 23:11:37 derick Exp $