PMX spam filter server and recieve emails for multiple domains in your exchange server

Recently, we receive alert from ISP about mail latency. Check Exchange server logs and everything looks fine. Compare logs. The process time between PMX and Exchange is quite short. In this case, either spam filter or routing is the source of the problem. Double check and no one has made any changes to the router.

Check the PMX server. The load and iostat is high. Looks like the bottleneck is on the local disk. Increase memory does not really help. The only other option is to take the database out and migrate it to another server. However, we don't have enough space in the rack since we plan to retire one more rack. We get an appliance from Sophos ES4000. Very easy to setup. Once installed, no more performace issue.

We only config inbound email pt to the appliance. Outbound email will bypass the appliance. Basically make sure routing is setup correctly (point to your exchange server). If you are config to receive emails for multiple domain, make sure include those domain in the PMX config. No more sendmail.mc, pmx.conf modification and recompile. Other than routing setup on the appliance, make sure you have MX record setup correctly on your DNS server and ISP. Also, make sure your recipient policy in your Exchange server include the other domains you are going to receive emails in your Exchange server.

For example, your company has a domain called first.com. Your Exchange server is config to receive email sent to first.com. However, you register another domain for your other product called second.com. You can receive emails sent to second.com on your Exchange server. First, contact your isp to add a MX record (may take 1 to 24 hrs to replicate). Then go to your DNS server (most likely ur DC and add the MX record) . Basically, point the MX record for second.com to your exchange server for first.com (for example, mail.first.com). Add second.com to the accepting mail domain in your PMX appliance. Lastly, goto your Exchange server default recipient policy, add SMTP for second.com. Force update the recipient policy so you can receive emails immediately for your second.com.