mikrotik-dhcp-auto-dns-register

:local DHCPtag
:set DHCPtag "#DHCP"

:if ( [ :len $leaseActIP ] <= 0 ) do={ :error "empty lease address" }

:if ( $leaseBound = 1 ) do=\
{
  :local ttl
  :local domain
  :local hostname
  :local fqdn
  :local leaseId
  :local comment

  /ip dhcp-server
  :set ttl [ get [ find name=$leaseServerName ] lease-time ]
  network 
  :set domain [ get [ find $leaseActIP in address ] domain ]
  
  .. lease
  :set leaseId [ find address=$leaseActIP ]

# Check for multiple active leases for the same IP address. It's weird and it shouldn't be, but just in case.

  :if ( [ :len $leaseId ] != 1) do=\
  {
   :log info "DHCP2DNS: not registering domain name for address $leaseActIP because of multiple active leases for $leaseActIP"
   :error "multiple active leases for $leaseActIP"
  }  

  :set hostname [ get $leaseId host-name ]
  :set comment [ get $leaseId comment ]
  /

  :if ( [ :len $hostname ] <= 0 ) do={ :set hostname $comment }

  :if ( [ :len $hostname ] <= 0 ) do=\
  {
    :log error "DHCP2DNS: not registering domain name for address $leaseActIP because of empty lease host-name or comment"
    :error "empty lease host-name or comment"
  }
  :if ( [ :len $domain ] <= 0 ) do=\
  {
    :log error "DHCP2DNS: not registering domain name for address $leaseActIP because of empty network domain name"
    :error "empty network domain name"
  }

  :set fqdn "$hostname.$domain"
  
  /ip dns static
  :if ( [ :len [ find name=$fqdn and address=$leaseActIP and disabled=no ] ] = 0 ) do=\
  {
    :log info "DHCP2DNS: registering static domain name $fqdn for address $leaseActIP with ttl $ttl"
    add address=$leaseActIP name=$fqdn ttl=$ttl comment=$DHCPtag disabled=no
  } else=\
  {
    :log error "DHCP2DNS: not registering domain name $fqdn for address $leaseActIP because of existing active static DNS entry with this name or address" 
  }
  /
} \
else=\
{
  /ip dns static
  :local dnsDhcpId 
  :set dnsDhcpId [ find address=$leaseActIP and comment=$DHCPtag ]

  :if ( [ :len $dnsDhcpId ] > 0 ) do=\
  {
    :log info "DHCP2DNS: removing static domain name(s) for address $leaseActIP"
    remove $dnsDhcpId
  }
  /
}