dhcp-to-dns: add a marker for new records

2 files changed, 11 insertions, 1 deletions

diff --git a/dhcp-to-dns b/dhcp-to-dns
index f88599c..f883cd0 100644
--- a/dhcp-to-dns
+++ b/dhcp-to-dns
@@ -21,6 +21,12 @@
 :local Ttl 5m;
 :local CommentPrefix "managed by dhcp-to-dns for ";
 
+:if ([ / ip dns static print count-only where comment="--- dhcp-to-dns above ---" name=- type=NXDOMAIN disabled ] = 0) do={
+  / ip dns static add comment="--- dhcp-to-dns above ---" name=- type=NXDOMAIN disabled=yes;
+  $LogPrintExit warning "Added disabled static dns record with comment '--- dhcp-to-dns above ---'." false;
+}
+:local PlaceBefore [ / ip dns static find where comment="--- dhcp-to-dns above ---" name=- type=NXDOMAIN disabled ];
+
 :foreach DnsRecord in=[ / ip dns static find where comment ~ $CommentPrefix ] do={
   :local DnsRecordVal [ / ip dns static get $DnsRecord ];
   :local MacAddress [ $CharacterReplace ($DnsRecordVal->"comment") $CommentPrefix "" ];
@@ -63,6 +69,6 @@
     }
   } else={
     $LogPrintExit info ("Adding new DNS entry for " . $Fqdn . ", address is " . $LeaseVal->"address" . ".") false;
-    / ip dns static add name=$Fqdn address=($LeaseVal->"address") ttl=$Ttl comment=$Comment;
+    / ip dns static add name=$Fqdn address=($LeaseVal->"address") ttl=$Ttl comment=$Comment place-before=$PlaceBefore;
   }
 }
diff --git a/doc/dhcp-to-dns.md b/doc/dhcp-to-dns.md
index 3f25659..9f8cb8b 100644
--- a/doc/dhcp-to-dns.md
+++ b/doc/dhcp-to-dns.md
@@ -25,6 +25,10 @@ A scheduler cares about cleanup:
 Configuration
 -------------
 
+On first run a disabled static dns record acting as marker (with comment
+"`--- dhcp-to-dns above ---`") is added. Move this entry to define where new
+entries are to be added.
+
 The configuration goes to `global-config-overlay`, these are the parameters:
 
 * `Domain`: the domain used for dns records