[exim] too many connections to smarthost

I'm forced to use my provider's smarthost. This is done by this
configuration:

smart_route:
driver = manualroute
same_domain_copy_routing = true
domains = !+local_domains:!+my_domains
transport = remote_smtp
host_find_failed = defer
route_list = "* mail.arcor.de bydns no_randomize"

As far as I understand, exim is supposed to use one connection for at
least 100 mails via this smarthost. Unfortunatly, it does not, and my
provider has a limit on the number of TCP connections in a given time.

Is this a bug in exim or a configuration error?

Please send replies cc to me, since I'm not subscribed to the list.



Exim version 4.69 #1 built 20-Jul-2010 09:16:20
Copyright (c) University of Cambridge 2006
Berkeley DB: Berkeley DB 4.5.20: (October 24, 2009)
Support for: crypteq iconv() IPv6 OpenSSL move_frozen_messages
Content_Scanning Old_Demime
Lookups: lsearch wildlsearch nwildlsearch iplsearch cdb dbm dbmnz dnsdb
dsearch ldap ldapdn ldapm nis nis0 passwd
Authenticators: cram_md5 dovecot plaintext
Routers: accept dnslookup ipliteral manualroute queryprogram redirect
Transports: appendfile/maildir/mailstore/mbx autoreply lmtp pipe smtp
Size of off_t: 8
Configuration file is /etc/exim/exim.conf