Messaging Server, RBL, and dns_verify
(Doc ID 1932937.1)
Last updated on OCTOBER 31, 2019
Applies to:Oracle Communications Messaging Server - Version 5.0.0 and later
Information in this document applies to any platform.
This article will address questions around the use of Real-time Block Lists (RBLs) and Domain Name Service (DNS) Verification in the Messaging Server MTA.
RBL and DNS Verification are actually separate things. But RBL checking makes use of dns_verify. This article is more about how to use the dns_verify routines.
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In this Document
|Questions and Answers|
|Do you really want to do this?|
|Realtime Block Lists (RBLs)|
|Normal DNS Usage by the MTA|
|Two things called DNS Verify|
|DNS Verify and RBL|
|Ok, How do I use this?|
|Options for configurating RBL|
|ENABLE_RBL or DNS_VERIFY_DOMAIN in dispatcher.cnf|
|The dns_verify library routines|
|A brief word about mappings tables|
|Use the dns_verify_domain_port routine in the PORT_ACCESS table|
|Use the dns_verify_domain routine in the MAIL_ACCESS or ORIG_MAIL_ACCESS tables|
|Syntax of dns_verify_domain and dns_verify_domain_port|
|Continuation Lines in Mappings Tables|
|Use the dns_verify (or dns_verify_ptr) routine in any table|
|The dns_verify_ptr argument syntax|
|Using dns_verify to do RBL lookups|
|When DNS fails - why you need return-if-indeterminate|
|Symbolic Substitution - Return Values|
|MTA Performance problems caused by RBL and DNS performance|
|Why is it so bad?|
|What else can we do about it?|
|Or have local users go thru a different service|
|Improvements in Messaging Server 6.3|