You have made it to the RBL page.
RBLs (Realtime Black Lists)
You are here because you might have previously attempted to send email and received a bounce email, or are looking to stop UCE (Unsolicited Commercial Email, formerly known as spam). To curb UCE, most companies are running a realtime black list. RBLs usually block about 75% of UCE, because they block IP addresses used to send UCE. RBLs are intented to only block repeat UCE offenders using the same IP address. When a sender of UCE changes their IP address, the RBL becomes useless. As with all RBLs, there is a high chance of blocking legitimate email because senders of UCE try to use legitimate IP addresses to get their so-called advertising out. This can irritate folks who use dynamic IP addressing, which in most part will be blocked.
The creation of a RBL is easy and simple and can be created as follows. The real problem with a RBL is keeping it up todate. Most senders of UCE move along by the time the list takes on its most profitable use. This is why http://spamcop.net and others have dropped the length from two weeks to just a few days. There are a few RBLs that will keep an IP entry on the list longer if it keeps attempting to send UCE.
The creation of a RBL is easy. Just follow these steps:
- Setup a DNS server of your choice
- We will use a reverse annotated IP entry (localhost will look like 1.0.0.127.blocklist.mydomain.example.com)
- Create an A record pointing to a local IP. I usually pick 127.0.0.2.
- Create a TXT record with the proper explanation. (This will be sent back to the sending MTA and relayed to an inbox. A good idea is to include a weblink or some other contact method for legitimate emailers. Most UCE offenders ignore this entry and move on.)
- Point your email server at your RBL domain and test away.
The main problem with RBLs is that using such a list give is that they give someone else control over the email you can receive. This can also be an excellent solution as the blocking happens on a per IP basis. Once a sender of UCE is found, everyone can block those message, but remember to unblock once they stop.
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