At last… I found the needle in the haystack. Wow, what a pain. We got our new email server all configured about 10 days ago, and it seemed to be working great for just about everyone. However, no one from with an aol.com email address was getting our emails.

After many many hours of searching I finally traced down what the issue was. This forum post from tek-tips.com was very helpful.

Quick Summary
AOL required reverse DNS to be configured for the IP address that is sending the email messages.

Full Details
This had all been configured correctly with our old email server, but when we migrated the the new email server, I had to change some of our firewall settings. The email server happens to accept request from a couple different IP addresses. So it was successfully receiving emails that were routed through mx1.checkoutmycards.com, but when it was sending emails it happen to go out through a different IP address.

I realized this by doing a “What is my IP” search and seeing that it didn’t match mx1.checkoutmycards.com. All I had to do was change one firewall setting so that outgoing emails got sent through the same IP address as the one that had reverse DNS configured.

I even created an @aol.com email address just to test the scenario and make sure things worked. Hopefully all of you at aol.com can now receive our emails.

This morning at 5:49AM PST I got a text from one of my employees that the site appeared to be down.

Sure enough our firewall was having issues and needed to be rebooted. Everything is back up and running fine now.

For a while I have been having http://mon.itor.us follow our site to track any down time. Since there haven’t been any issues is a very long time, I never spent the time to configure their setting to actively notify me of any down-time. So I went ahead and configured it so that I would get notified through email and text messaging if the site ever goes down. Normally they charge extra for text messages, but they offer free Twitter messages and Twitter offers free text messages… so that is a nice trick to get free text message of site status.

Now I should get notified pretty quickly if the site ever has connectivity issues, and I can make sure that you have as little down-time as possible.

You can now follow us on Twitter to get the latest updates on things related to CheckOutMyCards.com.

Sorry about the website slowness and sporadic down-time this morning. For some reason, Friday likes to give us the most fits. Almost every time we run into any issues it happens on a Friday. Go figure…

Anyhow… In case other web developers run into this issue, here is what happened, and what we did to fix it.

This morning we noticed that w3wp.exe on our web server was using nearly 100% of the CPU and was floating between 3GB and 6GB of memory usage.

Restarting IIS didn’t solve the problem. w3wp.exe would quickly consume all available resources.

Solution: Re-deploy the ASP.Net 2.0 website.

My theory is that the ASP.Net compile state somehow got corrupted. Re-deploying the website simply triggered a full recompile.

The website is back up and running smoothly now.

When you create an account at CheckOutMyCards.com our server sends you an email. Sometimes email from our server gets blocked by your email provider. The easiest way to unblock our email is to add staff@checkoutmycards.com to your contact list. To do that with Yahoo! Mail simply click on the Contacts tab or go to http://address.mail.yahoo.com.

Then click the Add Contact button.

Specify staff@checkoutmycards.com as the email address and click Save.

Now email from our server will arrive in your inbox and you will be able to activate your account.

To request a new activation email go to the following page, sign in (if necessary), and click the ‘Request a new activation email’ link.
http://www.checkoutmycards.com/manage/activate.aspx

Background
As part of the account creation process at CheckOutMyCards.com we verify that the user has specified a valid email address that can successfully receive email from our servers. This is very important for sellers on our site because they need to be notified if a potential buyer sends them an offer on their cards.

Unfortunately many people have trouble receiving email from our servers. In the past 30 days most email domains have had a 65-75% success rate in receiving our emails and activating their accounts. However there are two outliers, @yahoo.com and @gmail.com. As we have seen with just about everything from Google, their services appear to be superior. 95.74% of the users from @gmail.com successfully activate their accounts. Even though Yahoo! Mail is the post popular email provider it appears to be on the other end of the spectrum. Only 47% of the @yahoo.com email addresses are able to receive our emails.