Horse Sense

Iron Horse E-Mail Spam Blocking Policy

Iron Horse uses a variety of spam blocking mechanisms. Spam is a big problem. Over 90% of the mail we receive is spam. We want good mail to get through, but we can't afford to let it get buried in garbage. Ask us how we can keep your mail from being blocked and how to set up effective spam blocking that won't block mail you want to see.

We want to make sure that people know why they are blocked and how to send mail to us. We send back informative error messages when we block mail. Sometimes these messages aren't shown to the sender of the mail because their e mail server or their administrator edits out our message. Exchange servers do this a lot. Sorry, we can't fix a server configuration problem on your end, unless you ask us. If your e mail got rejected, we will be happy to tell your e mail administrator why it happened if it isn't in a return e mail you got from our server.

If your mail simply must get through, try this!

We exempt specific IP ranges and senders so we are sure that we can get their mail. It won't be blocked or greylisted. If you think your network addresses or domains need to be exempt from our anti-spam checks for some reason, please tell us.

We also allow anyone to send to the abuse@ih-online.com address. As long as they aren't sending banned file type, their mail will get through.

Some specifics on what types of mail we block or delay:

We use various checks on incoming mail to ensure it is coming from a legitimate source. These checks are widely used throughout the Internet. If we block or delay your mail, others will, too.

-Iron Horse ensures its authoritative DNS configuration is correct. Good forward and reverse DNS helps receiving e mail servers recognize Iron Horse mail as being legitimate. We also lock down our DNS and e mail servers so that it would be difficult to use them in spam or denial of service attacks on other networks. The information we put in DNS also keeps Iron Horse from being impersonated as a source of spam. Unfortunately, most companies we audit need to take these simple steps to improve their security and decrease their spam volume. Bad DNS information is probably the top reason we reject what might otherwise be "good" e mail.

-We use greylisting at Iron Horse to curb denial of service, directory harvesting, and spam attacks. If someone sends an e mail for the first time to someone at Iron Horse, the server will report back that it is too busy to accept their mail. Legitimate servers will try again, spammers won't. If you really must get that message through and think you are being affected by greylisting, try sending the same message again after waiting one minute. The downside of greylisting is that if we haven't seen your mail in a while, it will be delayed getting through until your server decides to resend it. Occasionally, people will also get a message from their own mail server saying their message has been delayed, but is still being retried. Rarely, a legitimate e mail server won't retry sending the mail (a violation of Internet standards). We are continually improving upon our e mail handling, so these issues are happening less and less.

-We check to make sure there is a mail server at the domain you are sending from. If someone sends mail from somewhere, but won't take it back, the mail is almost certainly bogus.

-We check to make sure that the HELO command that your server gives to ours is legal. Spammers often fail this check.

-E mail servers are required to have a reverse DNS record. It isn't supposed to have some variant of the IP address in it. It is supposed to match the name of the sending server. If it fails these checks, we block the mail.

-You can't send e mail to us claiming to be from our domain when you don't have a mailbox here.

-We compare the sender and the links being provided in e mails against lists of known spammers. If you get on one of these blocking lists, your mail will be blocked.

-If you send a link in a message containing an IP address instead of a name like www.ih-online.com as part of the URL, the mail will be blocked.

-If you send mail to someone that doesn't work at Iron Horse and then try to send to someone who does, your mail will get blocked.

-If you send an attachment that looks like one coming from common worms or is a "dangerous" attachment (usually something that could modify the behavior of a receiving machine if opened, our server will block that mail. If you want to sent us a "dangerous" file, like an executable file: (1) Tell us it is coming. (2) Rename the file to something that cannot be executed, like program.exe to program.txt.

If you have any questions regarding this policy or why a particular mailing got blocked, call us or e mail us at abuse@ih-online.com.

Tony Stirk

main site: www.ih-online.com