Lately, I've been receiving a lot of complaints about it taking a while for email to leave the outbox from my endusers. It's taking about 18 seconds to connect to the mailserver (according to our network monitoring server). It's been getting more noticable over the last week or two, so far I have seen no more than 65 SMTP threads (from doing ps auxw |grep -ic smtp) and from the server (telnet localhost 25) it is immediate. This is the only service that has this problem, all the other services respond in less than 1second or I would think it might be a network problem.
This is happening on zimbra 3.0.1 GA. I will be happy to provide any logs or configs that might be helpful.