The webtop admin has a basic email interface for testing email configuration on the server. This is fairly rudimentary as does not give any advice on what may or may not be wrong with the installation.
Might be nice to have something to this service that allows you to test email deliverability from an installation and to give you proper feedback on things that could be done to improve the deliverability of transactional emails.
Here is an example from the Discourse forum software:
From: firstname.lastname@example.org Date: Fri, Apr 11, 2014 at 2:12 PM Subject: [FarCry Dev Forum] Email Deliverability Test To: email@example.com This is a test email sent from your FarCry Dev Forum forum at: http://discourse.farcrycore.org Email deliverability is complicated. Here are a few important things you should check first: Know how to view the raw source of the email in your mail client, so you can examine the email headers for important clues. in Gmail, it is the "show original" option in the drop-down menu on each mail. IMPORTANT: Does your ISP have a reverse DNS record entered to associate the domain names and IP addresses you send mail from? Test your Reverse PTR record http://mxtoolbox.com/ReverseLookup.aspx here. If your ISP does not enter the proper reverse DNS pointer record, it's very unlikely any of your email will be delivered. Is your domain's SPF record correct? Test your SPF record http://www.kitterman.com/spf/validate.html here. Check to make sure the IPs of your mail server are not on any email blacklists http://whatismyipaddress.com/blacklist-check. Verify that your email server is definitely sending a fully-qualified hostname that resolves in DNS in its HELO message. If not, this will cause your email to be rejected by many mail services. Configure DKIM email key signing http://www.dkim.org/&url_id=3fb19886e0f014078cc4df698e13ba296740fb1e in your email software, and place the public DKIM key in your DNS records. This is not required, but will significantly improve email deliverability. (The easy way is to sign up for Mandrill http://mandrillapp.com, which has a generous free mailing plan and will be fine for small forums. You'll still need to set up the SPF and DKIM records in your DNS, though!) We hope you received this email deliverability test OK! Good luck, Your friends at Discourse http://discourse.org There should be an unsubscribe footer on every email you send, so let's mock one up. This email was sent by Name of Company, 55 Main Street, Anytown, USA 12345. If you would like to opt out of future emails, click here to unsubscribe