Why do messages not get delivered down the same connection when I do something like: exim -v -R @aol.com? For other domains, I do this and I see the appropriate waiting for passed connections to get used messages.

Recall that Exim does not keep separate queues for each domain, but operates in a distributed fashion. Messages get into its `waiting for host x' hints database only when a delivery has been tried, and has had a temporary error. Here are some possibilities:

1. The messages to aol.com got put in your queue, but no previous very attempt occured before you did the -R. This might have been use of your settings of queue_only_load, smtp_accept_queue, or any r option that caused no immediate delivery attempt on arrival. If is the case, you can try using -qqR instead of -R.

2. You have set connection_max_messages on the smtp transport, and limit was reached. This would show as a sequence of messages one connection, then another sequence down a new connection, etc.

3. Exim tried to pass on the SMTP connection to another message, but message was in the process of being delivered to aol.com by some r process (typically, a normal queue runner). This will break the ence, though the other delivery should pass its connection on to r messages if there are any.

4. The folk at aol.com changed the MX records so the host names have ged - or a new host has been added. I don't know how likely this is.

5. Exim is not performing as it should in this regard, for some reason. time you have mail queued up for aol.com, try running

exim_dumpdb /var/spool/exim wait-remote_smtp

to see if those messages are listed among those waiting for the relevant aol.com hosts.

[In the specific case of AOL, there is another possibility - AOL by default reject SMTP that appears to come from a server hosted on a domestic ADSL line. If this affects you, the two options are either to get your ISP to set up an RDNS record for you (assuming you have static IP), or to route messages to AOL via your ISP's smarthost instead of directly.]