#!rsc by RouterOS # RouterOS script: dhcp-to-dns # Copyright (c) 2013-2022 Christian Hesse # https://git.eworm.de/cgit/routeros-scripts/about/COPYING.md # # provides: lease-script, order=20 # # check DHCP leases and add/remove/update DNS entries # https://git.eworm.de/cgit/routeros-scripts/about/doc/dhcp-to-dns.md :local 0 "dhcp-to-dns"; :global GlobalFunctionsReady; :while ($GlobalFunctionsReady != true) do={ :delay 500ms; } :global Domain; :global HostNameInZone; :global Identity; :global PrefixInZone; :global ServerNameInZone; :global CharacterReplace; :global IfThenElse; :global LogPrintExit2; :global ScriptLock; $ScriptLock $0 false 10; :local Zone \ ([ $IfThenElse ($PrefixInZone = true) "dhcp." ] . \ [ $IfThenElse ($HostNameInZone = true) ($Identity . ".") ] . $Domain); :local Ttl 5m; :local CommentPrefix ("managed by " . $0 . " for "); :local CommentString ("--- " . $0 . " above ---"); :if ([ :len [ / ip dns static find where comment=$CommentString name=- type=NXDOMAIN disabled ] ] = 0) do={ / ip dns static add comment=$CommentString name=- type=NXDOMAIN disabled=yes; $LogPrintExit2 warning $0 ("Added disabled static dns record with comment '" . $CommentString . "'.") false; } :local PlaceBefore ([ / ip dns static find where comment=$CommentString name=- type=NXDOMAIN disabled ]->0); :foreach DnsRecord in=[ / ip dns static find where comment ~ $CommentPrefix ] do={ :local DnsRecordVal [ / ip dns static get $DnsRecord ]; :local MacAddress [ $CharacterReplace ($DnsRecordVal->"comment") $CommentPrefix "" ]; :if ([ :len [ / ip dhcp-server lease find where mac-address=$MacAddress address=($DnsRecordVal->"address") status=bound ] ] > 0) do={ $LogPrintExit2 debug $0 ("Lease for " . $MacAddress . " (" . $DnsRecordVal->"name" . ") still exists. Not deleting DNS entry.") false; } else={ :local Found false; $LogPrintExit2 info $0 ("Lease expired for " . $MacAddress . " (" . $DnsRecordVal->"name" . "), deleting DNS entry.") false; / ip dns static remove $DnsRecord; } } :foreach Lease in=[ / ip dhcp-server lease find where status=bound ] do={ :local LeaseVal; :do { :set LeaseVal [ / ip dhcp-server lease get $Lease ]; } on-error={ $LogPrintExit2 debug $0 ("A lease just vanished, ignoring.") false; } :if ([ :len ($LeaseVal->"address") ] > 0) do={ :local Comment ($CommentPrefix . $LeaseVal->"mac-address"); :local HostName [ $IfThenElse ([ :len ($LeaseVal->"host-name") ] = 0) \ [ $CharacterReplace ($LeaseVal->"mac-address") ":" "-" ] \ [ $CharacterReplace ($LeaseVal->"host-name") " " "" ] ]; :local Fqdn ($HostName . "." . [ $IfThenElse ($ServerNameInZone = true) ($LeaseVal->"server" . ".") ] . $Zone); :local DnsRecord [ / ip dns static find where name=$Fqdn ]; :if ([ :len $DnsRecord ] > 0) do={ :local DnsIp [ / ip dns static get $DnsRecord address ]; :local DupMacLeases [ / ip dhcp-server lease find where mac-address=($LeaseVal->"mac-address") status=bound ]; :if ([ :len $DupMacLeases ] > 1) do={ :set ($LeaseVal->"address") [ / ip dhcp-server lease get ($DupMacLeases->([ :len $DupMacLeases ] - 1)) address ]; } :if ([ :len ($LeaseVal->"host-name") ] > 0) do={ :local HostNameLeases [ / ip dhcp-server lease find where host-name=($LeaseVal->"host-name") status=bound ]; :if ([ :len $HostNameLeases ] > 1) do={ :set ($LeaseVal->"address") [ / ip dhcp-server lease get ($HostNameLeases->0) address ]; } } :if ($DnsIp = $LeaseVal->"address") do={ $LogPrintExit2 debug $0 ("DNS entry for " . $Fqdn . " does not need updating.") false; } else={ $LogPrintExit2 info $0 ("Replacing DNS entry for " . $Fqdn . ", new address is " . $LeaseVal->"address" . ".") false; / ip dns static set name=$Fqdn address=($LeaseVal->"address") ttl=$Ttl comment=$Comment $DnsRecord; } } else={ $LogPrintExit2 info $0 ("Adding new DNS entry for " . $Fqdn . ", address is " . $LeaseVal->"address" . ".") false; / ip dns static add name=$Fqdn address=($LeaseVal->"address") ttl=$Ttl comment=$Comment place-before=$PlaceBefore; } } else={ $LogPrintExit2 debug $0 ("No address available... Ignoring.") false; } }