The VPOP3 settings show the first 100 messages in the LAN forwarding queue. Usually this is sufficient as the LAN forwarding queue is usually nearly empty, but in case of a problem it may be much bigger. The database queries below may help in that situation.
At a command prompt in the VPOP3 directory run
psql
(The password is 'vpop3pass')
Then, type
SELECT sender,target,subject,r.username || '@' || r.domain as recipient FROM messages.outgoing INNER JOIN messages.outgoingrecipients r USING(msgid) INNER JOIN messages.outgoingtargets USING(msgid) ORDER BY msgid;
to list all the messages in the LAN forwarding queue
or use
SELECT count(*) FROM messages.outgoing;
to simply get a count of the number of messages in the queue
N.B. VPOP3 does not need to be stopped while you do this