Update Dez 2020: We made an update for users with BIND 9.16.
Update Nov 2017: DNSSEC zone signing as described here is outdated. We strongly recommend against the method described in this blog post. Newer BIND versions or other DNS software have greatly simplified DNSSEC signing.
With BIND 9.9, ISC introduced a new inline signing option for BIND 9. In earlier versions of BIND, you had to use the dnssec-signzone utility to sign your zone. With inline signing, however, BIND refreshes your signatures automatically, while you can still work on the unsigned zone file to make your changes.
This blog post explains how you can set up your zone with BIND inline signing. The zone we are using is called example.com. In addition, we look at how to roll over your keys. In our example, we do a Zone Signing Key (ZSK) rollover. We expect that you are already familiar with ISC BIND and have a basic understanding of DNSSEC. More specifically, you should be able to set up an authoritative-only name server and have read up on DNSSEC and maybe used some of its functions already.
Before we set up inline signing with BIND, let us look at a typical network architecture. We will set up inline signing on a hidden master name server. This server is only reachable from the Internet via one or more publicly reachable secondary name servers. We will only cover the configuration of the hidden master as the secondary name server configuration will not differ for the signed zone (assuming you are using DNSSEC-capable name server software).