Is Reliant on the blacklist?

[Jme574]

We got this in our email today, notice the

host gateway-r.comcast.net [204.127.198.26]: 550-67.18.4.2 blocked by ldapu=rblmx,dc=comcast,dc=net
550 Blocked for abuse. Please send blacklist removal requests to blacklist_comcastnet@cable.comcast.com - Be sure to include your mail server IP ADDRESS

towards the bottom of the email. Does that mean we are on the blacklist or they are on the blacklist? Where do you go to find out if your ip is on a blacklist?

Date: 3/22/2006 16:12:13 -0600
From: Mail Delivery System <Mailer-Daemon@reliant.websitewelcome.com>
To: xxxxx@indianadjs.com
Subject: Mail delivery failed: returning message to sender All headers
This message was created automatically by mail delivery software
A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:
tamisweeney-lee@comcast.net
SMTP error from remote mail server after MAIL FROM:<xxxxx@indianadjs.com> SIZE=2539:
host gateway-r.comcast.net [204.127.198.26]: 550-67.18.4.2 blocked by ldapu=rblmx,dc=comcast,dc=net
550 Blocked for abuse. Please send blacklist removal requests to blacklist_comcastnet@cable.comcast.com - Be sure to include your mail server IP ADDRESS.

[Sergio]

You can find if your server or any other server is blacklisted in www.dnsstuff.com, there is an option where you can enter the IP or the domain name, and it will show about 80 different lists where to check on.

Regards,
Sergio