Add documentation for ABI 5 related issues

diff --git a/docs/markdown/authoritative/backend-pipe.md b/docs/markdown/authoritative/backend-pipe.md
index a006beb014f3565c6e6affd9a86111679af573d9..682df3e5639987b5c9b907af5dc730dc4eeaac36 100644 (file)
--- a/docs/markdown/authoritative/backend-pipe.md
+++ b/docs/markdown/authoritative/backend-pipe.md
@@ -178,6 +178,16 @@ DATA    scopebits   auth    qname       qclass  qtype   ttl id  content
 
 For abi-versions 1 and 2, the two new fields fall back to default values. The default value for scopebits is 0. The default for auth is 1 (meaning authoritative).
 
+## Direct backend commands
+With abi-version 5 you can use [backend-cmd](dnssec.md#pdnssec) for executing commands on your backend. PowerDNS will use the following query/answer format
+```
+CMD    Whatever you wrote
+Answer goes here
+And can be multiple lines
+until we see
+END
+```
+
 ## Sample perl backend
 ```
 !!include=../modules/pipebackend/backend.pl