I have found that most of the common mis-spellings of our domain name
have been registered with the Internic by a company named Americaoffline.
Examples:
concentic.net
concentri.net
concnetric.net
consentric.net
They have also grabbed other mis-spellings of popular domains
Examples:
aool.com
bellsoth.com
bellsuth.com
hotmaiil.com
mailexite.com
pacbel.net
spraynet.com
Originally I thought they were using these to build a bulk email list.
Then I found they have configured ftp addresses in each domain. This
will allow them to gather valid usernames and passwords anytime someone
makes a typo and trys to upload something to their ISP.
We have listed their servers as bogus in our DNS configuration for now
and are looking into other more complete solutions.
Bind 8.X configuration addition:
server 205.231.48.243 { bogus yes; };
server 205.231.48.244 { bogus yes; };