How to use the JANET RBL+

Introduction

JANET(UK) has subscribed to certain services of Mail Abuse Prevention System LLC (MAPS, now part of Trend Micro) on behalf of all JANET customer organisations. This brief note includes quick-start instructions for mail system administrators wishing to use RBL+ in JANET.
There is a separate (longer) note "The MAPS RBL+ in JANET" for the information and guidance of those who manage or administer mail services within JANET organisations.

If you think JANET is blocking your mail

If you are outside JANET and you believe a JANET organization is blocking mail from you, please read the short separate note "How the JANET RBL+ affects you" before recording a complaint.

How to use the JANET RBL+

Most modern mailer programs have facilities for testing address lists in the style of the RBL (the original Realtime Blackhole List); indeed, some of them include lookups from the standard MAPS domains in their default configuration.

To use RBL+ in JANET, you need only change the zone within which the lookups are made.
Configuration for use outside JANET refers to a zone such as

rbl-plus.mail-abuse.org

or possibly to one or more of the three separate zones

blackholes.mail-abuse.org

relays.mail-abuse.org

dialups.mail-abuse.org

Within JANET, replace any or all of the above with a single reference to

rbl-plus.mail-abuse.ja.net

Detailed instructions (which file to edit, or which menu or command to use) will be in the documentation for your own mailer software.

Exchange server

If an Exchange server is configured to use RBL+, it will be able to reject at least half of the messages offered to it. These rejected messages require no processing whatsoever. Exchange 2003 supports this without additional software. Microsoft's instructions on how to configure connection filtering to use RBLs and how to configure recipient filtering in Exchange 2003 can be found at: http://support.microsoft.com/default.aspx?scid=kb;en-us;823866&Product=exch2003.

Conditions of use

Risks

Use of RBL-style lists carries some risks and responsibilities. JANET(UK)'s view is that for most JANET organisations the likely benefit (mainly through the substantial amount of Unsolicited Bulk E-mail rejected) justifies the possible drawbacks, but each organisation must make its own choice.

If you reject mail transfer attempts, you will lose some mail you or your users might have legitimately wanted. The amount should be small, but there may be a user support issue.
Specifically, you may want some of your own users to be able to send mail through your servers (and perhaps using your e-mail addresses) from other networks such as commercial dialup providers. Such networks may well be included in DUL and so in RBL+; this is in no way a suggestion that they are unsatisfactory and you may wish to give certain IP address ranges special treatment.
Some organisations may express irritation that you are blocking mail from them.
Application of RBL+ does not block all unwanted mail. If you notice specific addresses from which you get a lot of unwanted traffic, you should consider submitting them to MAPS for inclusion on the appropriate list. The MAPS Web pages for each separate list give details.

Protecting MAPS data

MAPS data is proprietary. You should take whatever precautions are necessary to prevent access from outside JANET.
Specifically, the DNS resolvers under your control MUST NOT accept recursive DNS queries from outside your own network for data in the JANET RBL+ zone. Note that it is ordinary good practice to prevent all such recursive lookups from outside.
The JANET operators will record the IP address of each resolver (or perhaps mail server) making lookups from the zone, and will test it from time to time to confirm that it correctly rejects recursive queries.

If it does indeed reject them, no action will be taken and it will be allowed to continue to lookup data from the zone.
If it permits access which it should not, the JANET operators will attempt to contact the person responsible for the IP address concerned, and will then help them to correct the faulty configuration. They may suggest workarounds if it proves difficult.
If for any reason it is not possible to implement a secure arrangement within a reasonable period, the operators will bar access to the zone from the IP address concerned.
To contact the operators if you believe you may have been barred, e-mail liaison@ja.net or phone 020 7692 1373.

Further information

For further details see the more explanatory JANET document "The MAPS RBL+ in JANET", or ask JANET Customer Service.

References

MAPS Overview of RBL
JANET pages:

More explanatory guide: "The MAPS RBL+ in JANET"
"Using RBL+ with Exim"; example of more selective use