We’ve received inquiries from customers who have used our Email Blacklist Tool to check their IP address and found it clean, except for the FIVETENFREE lookup. If this happens to you, our response depends on your answer to the following question: did this email blacklist cause you to have rejected email, or are you just being proactive?
The reason we ask this is that the FIVETENFREE email blacklist has been known to produce a relatively high percentage of false positives.
For example, my personal IP, given to my computer dynamically, is on their blacklist.
Here’s what their site says when I run the test on my current personal computer IP:
“misc.spam. If you are not running a mail server on (X), this listing should not affect you in any way, and you should ignore whatever source told you that this might be a problem.
The misc.spam group is mostly (but not entirely) composed of entire addresses blocks that have a) sent spam here, b) have consecutive or missing reverse dns, and c) have no customer sub-delegation via either the controlling RIR (ARIN, RIPE, LACNIC, APNIC, etc) or an rwhois server referenced in the main RIR records.”
So, the problem ends up being my IP address reverse-DNS doesn’t correspond to my domain name, and they also don’t like the TTL for my A record. Of course, none of this is under my control, it is controlled by my ISP.
So, as they suggest on their own site, I should ignore this.
We suggest you do the same unless it is causing email problems. To go to their site directly to test your own IP, and find out why it’s listed, go to: http://www.five-ten-sg.com/mapper