bind9 multiple RRs of singleon type

On an issue I have been working on a zone did not load on the bind9 server. When debugging I ran across the message "multiple RRs of singleon type". To find this error message I had to run named as "named -g -u bind -d 9". According to an article I found on this matter it is related to duplicate CNAMEs or SOA records on a zone.

I started out by looking into the zone file (sort zone.db) and quickly found two almost identical SOA records.

I deleted one line and after a quick reload of named everything started working.

Sender Policy framework

In the war against forged emails we have a new contender that seems promising. The name of the new contender is Sender Policy Framework. The specifications are outlined in RFC4408.

SPF works like a charm - when configured properly. For my domain helge.net I have added the following TXT record:

helge.net. 3600 IN TXT "v=spf1 mx -all"

By doing this I say that emails from my domain helge.net is only allowed to originate from my incoming mailserver.

Given this information the received can check to see if the receiving email is forged or not.

Sender address forgery is a threat to users and companies alike, and it even undermines the e-mail medium as a whole because it erodes people's confidence in its reliability. That is why your bank never sends you information about your account by e-mail and keeps making a point of that fact.

For this to work you need to add a TXT record to your domain. At the project homepage you can find out for yourself how to do so.