#!rsc # RouterOS script: dhcp-to-dns # Copyright (c) 2013-2019 Christian Hesse # # check DHCP leases and add/remove/update DNS entries :global CharacterReplace; :global Identity; :global Domain; :global HostNameInZone; :local Zone; :if ($HostNameInZone = true) do={ :set Zone ("dhcp." . $Identity . "." . $Domain); } else={ :set Zone ("dhcp." . $Domain); } :local Ttl 5m; :local CommentPrefix "managed by dhcp-to-dns for "; :foreach Static in=[ / ip dns static find where comment ~ $CommentPrefix ] do={ :local MacAddress [ $CharacterReplace [ / ip dns static get $Static comment ] $CommentPrefix "" ]; :local IpAddress [ / ip dns static get $Static address ]; :local HostName [ / ip dns static get $Static name ]; :if ([ / ip dhcp-server lease print count-only where mac-address=$MacAddress address=$IpAddress dynamic=yes ] > 0) do={ :log debug ("Lease for " . $MacAddress . " (" . $HostName . ") still exists. Not deleting DNS entry."); } else={ :local Found false; :log info ("Lease expired for " . $MacAddress . " (" . $HostName . "), deleting DNS entry."); / ip dns static remove $Static; } } :foreach Lease in=[ / ip dhcp-server lease find where dynamic=yes ] do={ :local Mac [ / ip dhcp-server lease get $Lease mac-address ]; :local DhcpIp [ / ip dhcp-server lease get $Lease address ]; :local Comment ($CommentPrefix . $Mac); :local HostName [ $CharacterReplace [ / ip dhcp-server lease get $Lease host-name ] " " "" ]; :if ($HostName = "") do={ :set HostName [ $CharacterReplace [ / ip dhcp-server lease get $Lease mac-address ] ":" "-" ]; } :local Fqdn ($HostName . "." . $Zone); :local DnsNode [ / ip dns static find where name=$Fqdn ]; :if ([ :len $DnsNode ] > 0) do={ :local DnsIp [ / ip dns static get $DnsNode address ]; :local Leases [ / ip dhcp-server lease find where host-name=$HostName dynamic=yes ]; :local HostNameCount [ / ip dhcp-server lease print count-only where host-name=$HostName dynamic=yes ]; :if ($HostNameCount > 1) do={ :foreach J,Lease in=$Leases do={ :if ($J + 1 = $HostNameCount) do={ :set DhcpIp [ / ip dhcp-server lease get $Lease address ]; } } } :if ($DnsIp = $DhcpIp) do={ :log debug ("DNS entry for " . $Fqdn . " does not need updating."); } else={ :log info ("Replacing DNS entry for " . $Fqdn . ", new address is " . $DhcpIp . "."); / ip dns static set name=$Fqdn address=$DhcpIp ttl=$Ttl comment=$Comment $DnsNode; } } else={ :log info ("Adding new DNS entry for " . $Fqdn . ", address is " . $DhcpIp . "."); / ip dns static add name=$Fqdn address=$DhcpIp ttl=$Ttl comment=$Comment; } }