Has your school mailserver been blacklisted?

8th August 2007

posted in edtech, isafety |

The continuing proliferation of spam and phishing schemes are being driven by many factors, but identity theft figures prominently on that list. For organizations with a large number of Windows-based computers, including school districts, one unfortunate side effect of teachers, students, or others unwittingly installing malware on a Windows-based computer system is that the organizational mail server can be “blacklisted.”

This is a problem if anyone in the organization which has been “blacklisted” is interested in SENDING email to someone outside the organization. When a mailserver is blacklisted, it can RECEIVE but not SEND email.

NewNet66 is a non-profit consortium of Oklahoma schools, and has created a website which will show you your IP address and then link to other websites you can use to learn if your school district’s IP address range has been blacklisted. This website tool should work for any location, whether or not the school or organization is part of the NewNet66 consortium. Link to the tool on: www.newnet66.org/ipaddress/. Two links are available to use for blacklist checking, one from Spamhaus and another from Spamcop:

If your school district or organizational website IS blacklisted, your network administrator can find more information about getting “unlisted” on the above websites.

On this day..

This entry was posted on Wednesday, August 8th, 2007 at 3:08 pm and is filed under edtech, isafety. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

1 On August 8th, 2007, Mathew said:

Do you know how to look up your home account if you have a dynamic IP address?

2 On August 8th, 2007, Wesley Fryer said:

I am not sure why you would need to– if you are running your own mail server you would have a static IP address– some ISPs block outgoing mail through SMTP servers that are NOT their own, I know Cox does this here in the midwestern U.S. I don’t think a dynamic residential IP address would be whitelisted. The same website will show you your “outside” dyanamic IP address, however, so you could give it a try.

3 On August 8th, 2007, Identity 2.0 » Blog Archive » Has your school mailserver been blacklisted? said:

[...] Has your school mailserver been blacklisted? Identity [...]

4 On August 8th, 2007, Stephanie Sandifer said:

Wesley —

I recently experienced a similar issue with blacklisting of my server IP address from the server that hosts all of my websites. I have some email accounts associated with some of the websites and the main email account was “spoofed” and/or hacked and used for spam which resulted in the IP address being blacklisted. don’t ask me how “spoofing” works — I have no clue other than it basically means that a spammer or phisher can send emails that appear to originate from your domain. A hacked account can occur if there are any “holes” in any of the websites (or their backends) that you use for your websites.

Here is the important point about this that I learned from my experience. If an IP address is blacklisted by Yahoo!, not only will you not be able to email Yahoo.com email addresses, but yahoo.com email addresses will also not be able to email any address at the domains associated at the blacklisted IP address.

I tested this using my domains and a personal yahoo.com email address that I use infrequently. I was unable to send any emails from my yahoo.com address to any email account associated with any of my hosted domains. My understanding is that the only solution is for the network admin to contact Yahoo! and appeal to them to remove the IP from their blacklist (which they are reluctant to do once an IP has been identified as being associated with spam).

Fortunately I don’t use an email account associated with the domain for my blog, but it has affected my ability to communicate with a small alumni group for my alma mater.

Thanks for posting this information as it is very important info for anyone involved with server, website, or email administration.

Stephanie

5 On August 8th, 2007, Mathew said:

I feel for Stephanie. My web site has a mailing list. It’s not spam because people sign up for it (and of course it’s educational in nature). But because it is bulk mail, some spam filters consider it spam. Spam Barracuda blocks me whenver I include my signature. I take heart in the fact that Discovery Educator’s newsletter ends up in my google junk mail folder more often than not…so I’m in good company.

6 On August 9th, 2007, Brian B. said:

My school’s mail server got blacklisted by two different spam protection sources. We watched our outgoing traffic via live firewall logs and found the internal IP address of the spam generator and viola - 4 trojans on a laptop. It was a busy boy sending spam from our external IP address.

/begin sarcasm

Cheers to whoever wrote those trojans - I surely didn’t have enough to do.

/end sarcasm

7 On October 20th, 2007, gregory said: