#!rsc # RouterOS script: dhcp-to-dns # Copyright (c) 2013-2018 Christian Hesse <mail@eworm.de> # # check DHCP leases and add/remove/update DNS entries :global "identity"; :global "domain"; :global "hostname-in-zone"; :local zone; :if ($"hostname-in-zone" = true) do={ :set zone ("dhcp." . $identity . "." . $domain); } else={ :set zone ("dhcp." . $domain); } :local ttl "00:05:00"; :local hostname; :local fqdn; :local dnsip; :local dhcpip; :local dnsnode; :local dhcpnode; :foreach static in=[ / ip dns static find where name ~ (".*\\." . $zone) ] do={ :set fqdn [ / ip dns static get $static name ]; :set hostname [ :pick $fqdn 0 ( [ :len $fqdn ] - ( [ :len $zone ] + 1 ) ) ]; :set dhcpnode [ / ip dhcp-server lease find where host-name=$hostname dynamic=yes ]; :if ( [ :len $dhcpnode ] > 0) do={ :log debug ("Lease for " . $hostname . " still exists. Not deleting."); } else={ :local found false; :log info ("Lease expired for " . $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 ]; :set dhcpip [ / ip dhcp-server lease get $lease address ]; :local comment ("managed by dhcp-to-dns for " . $mac); :set hostname [ / ip dhcp-server lease get $lease host-name ]; :while ($hostname ~ " ") do={ :local pos [ :find $hostname " " ]; :set hostname ( [ :pick $hostname 0 $pos ] . [ :pick $hostname ($pos + 1) 999 ] ); }; :if ( [ :len $hostname ] > 0) do={ :set fqdn ( $hostname . "." . $zone ); :set dnsnode [ / ip dns static find where name=$fqdn ]; :if ( [ :len $dnsnode ] > 0 ) do={ :set dnsip [ / ip dns static get $dnsnode address ]; :local leases [ / ip dhcp-server lease find where host-name=$hostname dynamic=yes ]; :local hostnamecount [ :len [ / ip dhcp-server lease find 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; } } }