Company mail server being used as a spam relay

Posted on 2012-08-15
Last Modified: 2012-08-15

Our Imail server is being used to relay large amounts of spam. The spam fills the spool, backs up legitimate messages, and sometimes even crashes the Imail. This is a huge problem for us as we manage email domains for external clients and they are affected by this.

My colleague and I are baffled as to how the spammer is pulling this off. For one, we have Imail configured to only send mail to domains that we manage. It is specifically configured not to send any email to outside domains (Yahoo, Hotmail, Gmail, ect... where most of the spam is going). Additionally, we've added the spammer's email to Imail's "kill list" which should block him, but he is still getting through. I've looking up the IP that the spam is coming from and blocked port 25 for that IP on our firewall. Somehow, spam is still getting through.

After blocking the email and IP, spam continued to come in (and be relayed successfully) from the email account in question. After a few hours, spam started coming in from a new email address. Experts, we are baffled! Please, any suggestions would be appreciated. I can provide any other info you may need.

Thank you!
Question by:coldfirenj

    Author Comment

    Spammers in question... &
    LVL 12

    Expert Comment

    LVL 9

    Accepted Solution


    No Mail Relay

    With this option, IMail will not relay mail through the server unless the sending user authenticates. On the SMTP Security tab, make sure that 'Disable SMTP "AUTH" reporting' is NOT selected. (In version 8 and higher, this option is on the SMTP Advanced tab).

    No Mail Relay is the best solution for customers who are unable to choose 'Relay mail for Addresses' because their users connect using dynamic IP Addresses.

    Author Closing Comment

    Thank you Bill

    Write Comment

    Please enter a first name

    Please enter a last name

    We will never share this with anyone.

    Featured Post

    Do email signature updates give you a headache?

    Constantly trying to correctly format email signatures? Spending all of your time at every user’s desk to make updates? Want high-quality HTML signatures on all devices, including on mobiles and Macs? Then, let Exclaimer solve all your email signature problems today!

    Article by: Rob
    Notes 8.5 Archiving Steps and Tips This article covers setting up a Notes archive, and helps understand some of the menu choices making setting up and maintaining a Notes archive file easier.
    The purpose of this video is to demonstrate how to use PicMonkey software to customize images for a Mailchimp campaign. Picmonkey is free and simple online software which can be used by users who don’t have robust editing software such as Photoshop,…
    In this Experts Exchange video Micro Tutorial, I'm going to show how small business owners who use Google Apps can save money by setting up what is called a catch-all email address in their Gmail accounts. By using the catch-all feature, small busin…

    779 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    17 Experts available now in Live!

    Get 1:1 Help Now