First thing is to send them the money. $200/year [Sep-2002]. (Click MAPS link above, find "Subscription Policies" link, then "Fee structure" link.) They will email you when your check arrives. There may be a delay for a day or so before they approve your subscription. They will then email you with acknowledgement that your IP address has been enabled.

When you send in your money, they will need:

• Your machines IP address. Please note that you must have a fixed IP address. If your machine answers to multiple IP addresses, you may have problems (I don't have this config -- this is a warning from RBL Tech Supp.).
• Your email address. This cannot be fake, it's the real contact info. Without it, you're out of luck.
• The appropriate contract from the Fee Structure page.
• And of course, your money

On your server, you need to make the following config changes:

• You should be using M4 for sendmail config. If not, this is the time to make the change. Trust me, it's worth it.
• In your .mc file, simply add:
  FEATURE(dnsbl, `rbl-plus.mail-abuse.org')
  or, if you prefer a more specific response to spam, something like this:
  FEATURE(dnsbl, `rbl-plus.mail-abuse.org', `"550 Mail from " $&{client_addr} " rejected; see http://mail-abuse.org/cgi-bin/lookup?" $&{client_addr}')
  A note on .mc files: Anything following a "dnl" is a comment. You do not need a trailing "dnl" on .mc file lines, regardless of how many examples of this you see on the web. You can test this yourself, by 'make'ing your config file, then removing all trailing "dnl"s, remaking the file and 'diff'ing them.
• Check your DNS configuration (/etc/named/namd.conf) -- you cannot use "forwarder"s. Remember that RBL-PLUS is specifically configured to allow your server to make queries -- it is unlikely that your forwarder(s) are also enabled -- if it is, you just saved yourself $200!
  Note: when sendmail makes a request to RBL-PLUS, it simply does a direct DNS lookup of a hypothetical address at mail-abuse.org.

• Check your logs (/var/log/maillog) -- search for rbl-. If it's working, you'll see "status=reject" entries.

• Use 'named-xfer' to fetch the public systems at mail-abuse.org.
  At this time you'll find west1, east1, and europe1 -- you may want to use one of these others as your configured default.
• Use 'traceroute' to see if you can contact west1.mail-abuse.org. Try 127.0.0.2 -- lookups are done backwards:
  

  > # nslookup
  Default Server:  [my server/address edited out]
  Address:  [my server/address edited out]
  
  > 2.0.0.127.rbl-plus.mail-abuse.org
  Server:  [my server/address edited out]
  Address:  [my server/address edited out]
  
  Name:    2.0.0.127.rbl-plus.mail-abuse.org
  Address:  127.1.0.5
  
  > # 
  

  If you get a "host/domain not found" error, it's not working. Possibly MAPS has not enabled your IP, or you're going through a forwarder.
• Test if MAPS is talking to you:
  Do the same test as above, but ask their server directly. (Use the zone load from above to determine their server IP addresses.) Use the magic address 127.0.0.2 (in reverse order). If you're not enabled at their end, you'll get a timeout error:

  # nslookup
  Default Server:  [my server/address edited out]
  Address:  [my server/address edited out]
  
  > server 157.22.13.82
  Default Server:  82.13.22.157.zocalo.net
  Address:  157.22.13.82
  
  > 2.0.0.127.rbl-plus.mail-abuse.org
  Server:  82.13.22.157.zocalo.net
  Address:  157.22.13.82
  
  Name:    2.0.0.127.rbl-plus.mail-abuse.org
  Address:  127.1.0.5
  
  > #