The problem:
Spam. Because networks of either being friendly to
spammers, or
neutral to, spammers take advantage of this and send email from a particular network. End users don't like spam.
One solution:
After numerous accounts of spam email from a site and failure for some reason or another to reach an agreement with the site owners, that site may be put on the RBL. The reasons for being put on the RBL are numerous but single minded - stop unsolicited bulk email.
- badly managed opt-out lists from large companies
- an open SMTP relay
- hosting services in support of unsolicited bulk email
- hosting web pages promoted by UBE
- providing email boxes and/or autoresponders promoted by UBE
- providing resources such as DNS, banner ads, hit counters,
script processing, form handlers to sites promoted by spam.
- providing software or services for distributing spam
- hosting web pages or providing connectivity to those who provide software or services for UBE.
- providing credit card processing or other online payment services for goods and services promoted by UBE
- providing adult verification services to sites promoted by spam
- providing email address by any other means than opt-in.
- continuing to provide service to customers providing spam support
services after this has been brought to the provider's attention.
People who subscribe to this DNS services may block out the
networks
that are listed. This can be anything from a simple
sendmail ruleset that drops mail from a site or network on the RBL to placing these sites and networks in the
router and effectively removing them from your view of the network.
http://mail-abuse.org/rbl/