RFC1912 2.1 says you should have a reverse DNS for all your mail servers.
Edward W. Ray CISSP, MCSE 2003+Security, P.E. GCIA, GCIH NetSec Design & Consulting -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Paul Schmehl Sent: Thursday, March 10, 2005 7:58 AM To: [email protected] Subject: [Full-disclosure] Reverse dns Is there an RFC *requirement* for reverse dns? I've been looking through the RFCs and I can't find it. Some folks think reverse dns should be completely disabled. I know for sure that this will break email, because many mail servers won't talk to a server that doesn't reverse. Tcpdump also doesn't like hosts that won't reverse. What I'm looking for is a standard (RFC) that states that enabling reverse lookups is *required* or reverse lookups are *optional*. If they're optional, then reverse could be disabled for most hosts. I'm also looking for a list of things that *break* when you disable reverse (e.g. mail). RULES FOR RESPONDING: 1) "Reverse is a good thing" is not an answer. Neither is "Reverse is a bad thing". 2) Opinions are not useful - stick to facts only - chapter and verse please. 3) All replies to the list please - others will find this useful as well. Paul Schmehl ([EMAIL PROTECTED]) Adjunct Information Security Officer The University of Texas at Dallas AVIEN Founding Member http://www.utdallas.edu _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://www.secunia.com/ _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://www.secunia.com/
