Bug: duplicate message ids

Hi,

I'm using log4j-1.2.13 in a tomcat webapp. I've configured log4j to send an 
email for errors of category ERROR and higher. Our old configuration was
SUN's javamail-1.3.1-2jpp and tomcat5-5.0.30-11jpp. The generated message 
ids were of the format

30810565.1172372608329.JavaMail.tomcat4@<fqdn of the server>

tomcat4 is the UNIX user of the tomcat5 installation. The numbers were 
constantly changing, so we had no duplicate message ids.

No we moved to a new system where we use classpathx-mail-1.1-1jpp and 
tomcat55-5.5.17-4jpp. The format of the message ids is now

1677625.1177554343570.JavaMail.tomcat@<only hostname of the server>

tomcat is the UNIX user of the tomcat55 installation. The numbers are not 
constantly changing, so we have lots of duplicate message ids.
The problem is, that my cyrus-imapd eliminates all mails with the same 
message id, so we're losing a lot of mails here.

As I don't know who creates these message ids I'm asking you if that could 
be a javamail problem or a log4j problem.

Best regards,
	boris