Can two server blocks in mail module listen the same port

[speedfirst]

When I config nginx like this, it reports: "starting nginx...2010/10/12
11:44:04 [emerg] 14955#0: duplicate "143" address
and port pair in /opt/nginx/nginx.conf.mail.imap:19"
Is there something I did wrong or nginx doesn't support this?

# IMAP proxy configuration
#
server
{
    server_name        test.com;
    listen                  143;
    protocol                imap;
    proxy                   on;
    sasl_service_name       "imap";
    starttls                only;
    ssl_certificate         /opt/certs/test.com.crt;
    ssl_certificate_key     /opt/certs/test.com.key;
}


server
{
    server_name         foo.com;
    listen                  143;
    protocol                imap;
    proxy                   on;
    sasl_service_name       "imap";
    starttls                only;
    ssl_certificate         /opt/certs/foo.com.crt;
    ssl_certificate_key    /opt/certs/foo.com.key;
}

server
{
    #server_name         default;
    listen                  143;
    protocol                imap;
    proxy                   on;
    sasl_service_name       "imap";
    starttls                only;
    ssl_certificate         /opt/certs/nginx.crt;
    ssl_certificate_key    /opt/certs/nginx.key;
}

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,140361,140361#msg-140361