How JANET DNSBLs affect you

A JANET mail server is blocking me. Why?

Many JANET organisations use one or more of the JANET DNS BlockLists (Spamhaus Zen and MAPS RBL+) to refuse mail connections from listed IP addresses. JANET endorses this use but does not manage the content of the lists concerned.

To find whether your mail server is on the list, fill in its IP address at
http://www.spamhaus.org/sbl/index.lasso (for SBL, XBL, PBL, Zen)
or
http://mail-abuse.com/lookup.html (for RBL, RSS, DUL, RBL+).

What can I do about it?

You should be able to tell from the above lookup pages which of the lists and component lists you are on. The criteria for listing, and the action you should take, are summarised later in  this note (Component lists).

What can JANET do about it?

JANET encourages customer organisations to use the Spamhaus Zen lists, the MAPS RBL+ or both. If you believe you are prevented from sending mail because you are listed there (or in the JANET Zen lists or JANET RBL+ which are our replicas), our advice to you is to follow the instructions for the list concerned.

Note that there may be a delay of a few hours between removal of an entry from RBL+ and its disappearance from the JANET replica. For the Zen lists the latency should be no more than an hour.

If you believe your IP address is not listed and a JANET customer organisation is refusing e-mail from you for some other reason, please contact the JANET Service Desk (URL below).

Other causes of e-mail blocking

JANET does not endorse the use of any DNSBLs other than the two sets mentioned here, but individual customer organisations are free to make their own choices about domains or IP addresses from which they do not wish to accept e-mail.

Many other DNSBLs are available, each with their own criteria for listing and removal from the list.

Component lists

Spamhaus

• SBL (Spamhaus Block List)
  lists the IP addresses of direct UBE sources, spam services and spammers themselves.
  Anyone on SBL will have to demonstrate that they now follow good practice.
• XBL (Exploits Block List)
  lists addresses which are victims of illegal third party exploits, including proxies, worms and trojan exploits.
  Ensure that your computer or computers are clean of infection and not under the control of an unauthorised third party.
• PBL (Policy Block List)
  lists IP address ranges whose owners' policy is that they are not expected to be used directly for outbound e-mail.
  The IP address of your mailer is in a service provider's consumer facilities and it is not expected to connect directly to other people's mail servers.
  Either send mail through your service provider's outgoing server (possibly called their "SMTP server" or "smarthost")
  or ask your own service provider for help.

Zen is the union of SBL, XBL and PBL; IP addresses are in Zen if and only if they meet the criteria for one or more of the other three.

MAPS

• RBL (the Real-time Blackhole List)
  Your mailer was listed because you or your service provider do not take measures to prevent UBE.
  Either you or your service provider will have to resolve the matter with MAPS.
• RSS (Relay Spam Stopper)
  Your mailer was listed because it was insecure and was available for unauthorised relaying of messages such as Unsolicited Bulk E-mail.
  Configure it so that is secure against relaying.
• DUL (Dial-up User List)
  The IP address of your mailer is in a service provider's consumer facilities and it is not expected to connect directly to other people's mail servers.
  Either send mail through your service provider's outgoing server (possibly called their "SMTP server" or "smarthost")
  or ask your own service provider for help.

RBL+ is the union of RBL, RSS and DUL.

Further information

Spamhaus pages:

• http://www.spamhaus.org/
• Look up an IP address: http://www.spamhaus.org/sbl/index.lasso

MAPS pages:

• Overview of RBL+: http://mail-abuse.com/wp_introrbl.html
• Look up an IP address:  http://mail-abuse.com/lookup.html
• RBL: http://mail-abuse.com/enduserinfo_rbl.html
• RSS: http://mail-abuse.com/enduserinfo_rss.html
• Anti-relaying advice: http://www.mail-abuse.com/an_sec3rdparty.html
• Testing and removal: http://work-rss.mail-abuse.org/rss/howtofix.html
• DUL: http://mail-abuse.com/enduserinfo_dul.html

One of several lists of other address lists:

• Declude: http://www.declude.com/Articles.asp?ID=97

JANET pages:

• JANET Service Desk (for any questions): http://www.webarchive.ja.net/services/connections
• "The Spamhaus Zen lists in JANET"
• "The MAPS RBL+ in JANET"