From 020f1772edd93798504781e2c3d499e10c0657d0 Mon Sep 17 00:00:00 2001
From: Nick Trochalakis <Chewbaccalakis@users.noreply.github.com>
Date: Fri, 23 May 2025 21:34:25 -0700
Subject: [PATCH] Create microtik_ptr_script

---
 microtik_ptr_script | 80 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 microtik_ptr_script

diff --git a/microtik_ptr_script b/microtik_ptr_script
new file mode 100644
index 0000000..8f2f4c8
--- /dev/null
+++ b/microtik_ptr_script
@@ -0,0 +1,80 @@
+# MikroTik (RouterOS) script for automatically setting DNS records
+# for clients when they obtain a DHCP lease.
+#
+# author SmartFinn <https://gist.github.com/SmartFinn>
+# based on https://github.com/karrots/ROS-DDNS
+
+:local domain;
+:local fqdn;
+:local hostname;
+:local safeHostname;
+:local token "$leaseServerName-$leaseActMAC";
+:local ttl [/ip dhcp-server get $leaseServerName lease-time];
+
+# Getting the domain name from DHCP server. If a domain name is not
+# specified will use hostname only
+
+/ip dhcp-server network {
+:do {
+:set domain [get [find where ($leaseActIP in address)] domain];
+
+# Add a dot before domain name
+
+:set domain ("." . $domain);
+} on-error={
+:set domain "";
+};
+};
+:if ($leaseBound = 1) do={
+:log debug "$leaseServerName: Processing bound lease $leaseActMAC ($leaseActIP)";
+/ip dhcp-server lease {
+:set hostname [get [find active-mac-address=$leaseActMAC] host-name];
+};
+
+# Delete unallowed chars from the hostname
+
+:for i from=0 to=([:len $hostname]-1) do={
+:local char [:pick $hostname $i];
+:if ($char~"[a-zA-Z0-9-]") do={
+:set safeHostname ($safeHostname . $char);
+};
+};
+:if ([:len $safeHostname] > 0) do={
+:set fqdn ($safeHostname . $domain);
+/ip dns static {
+:local itemId [find name=$fqdn];
+:if ($itemId != "") do={
+
+# This DNS entry already exists
+
+:if ([get $itemId comment] = $token) do={
+:if ([get $itemId address] != $leaseActIP) do={
+set $itemId address=$leaseActIP ttl=$ttl;
+:log info "Update DNS entry: $fqdn -> $leaseActIP ($leaseActMAC)";
+};
+} else={
+:log warning "Cannot to add DNS entry. $fqdn already exists";
+};
+} else={
+
+# Add DNS entry if it does not exist
+
+add name=$fqdn address=$leaseActIP ttl=$ttl comment=$token;
+:log info "Add DNS entry: $fqdn -> $leaseActIP ($leaseActMAC)";
+};
+};
+};
+} else={
+
+# Remove entry when lease expires ($leaseBound=0)
+
+:log debug "$leaseServerName: Processing deassigned lease $leaseActMAC ($leaseActIP)";
+/ip dns static {
+:local itemId [find comment=$token];
+:if ($itemId != "") do={
+:set fqdn ([get $itemId name]);
+remove $itemId;
+:log info "Remove DNS entry: $fqdn -> $leaseActIP ($leaseActMAC)";
+};
+};
+};