RDNS_NONE hits when it shouldn't
mark at msapiro.net
Wed Oct 21 16:12:51 UTC 2015
On 10/21/2015 01:05 AM, gojensen wrote:
> We sometimes have issues with mail being flagged because of the
> RDNS_NONE (Delivered to internal network by a host with no rDNS).
> In essence this means that the senders IP address has no correct DNS
> setup. However, when we try do nslookup on the mailscanner machine with
> those IP addresses they resolve just fine.
That is not the issue.
A properly configured mail server will identify itself in HELO or EHLO
as say example.com.
dig A example.com
(or nslookup) will return 111.222.333.444 as the IP address of
example.com and this should be the IP address of the connecting server.
dig -x 111.222.333.444
should return a PTR record back to example.com. RDNS_NONE says that
there is no PTR record in DNS for 444.333.222.111.in-addr.arpa.
Mark Sapiro <mark at msapiro.net> The highway is for gamblers,
San Francisco Bay Area, California better use your sense - B. Dylan
More information about the MailScanner