VPN Wake On LAN without DHCP

RouterOS Scripting
1

Hi,
I was asked if it was possible to wake up internal pcs automatically when they are accessed the first time over VPN (RDP). Since dhcp isn’t used, I had to create an arp/IP mapping.

I used the following rules and script in order to achieve it:

  1. Create a firewall rule that adds the target PC to an address list that is processed by a script, the rule should only trigger if the packets are originating from the VPN Pool (vvv.vvv.vvv.0/24)
add action=add-dst-to-address-list address-list=wol address-list-timeout=\
    none-dynamic chain=forward comment=\
    "packet from OVPN to 3389 add dest host to wol address-list" dst-port=3389 \
    protocol=tcp src-address=vvv.vvv.vvv.0/24
  1. Create static disabled arp entries on an unused interface (ether5). These entries should be maintained manually.
/ip arp add address=192.168.xx.1 interface=ether5 disabled=yes mac-address=EE:EE:EE:EE:EE:E1 comment=PC1
/ip arp add address=192.168.xx.2 interface=ether5 disabled=yes mac-address=EE:EE:EE:EE:EE:E2 comment=PC2
  1. Write a lookup script that parses the wol address-list every 5 seconds looking up the arp entry and sends the magic packet to that address (over the right interface). After sending the WoL packet the address is removed from that list.
       :local interface B1;
       
       :foreach i in=[/ip firewall address-list find where list=wol] do={
         :local wakeAddress [/ip firewall address-list get $i address];
         :foreach j in=[/ip arp find where address=$wakeAddress and interface=ether5] do={
           :local wakeMacAddress [/ip arp get $j mac-address];
           :log info "Sending WoL to $wakeMacAddress via $interface";
           /tool wol mac=$wakeMacAddress interface=$interface
         }
         /ip firewall address-list remove $i;

it works! Any comments appreciated.

Ralf.

2

Why not instead use a WOL software, there are many and free, wake your Computer, get Informed as soon as it is active and then do your RDP Session ?

What is the practical reason for waking a Computer up on the first attempt of an RDP Session ? Just wondering…

3

Zacharias, there are remote users in homeoffice, technically unskilled, but able to switch on the VPN client and start a RDP session. That alone will wakeup the office PCs without any additional tool. RDP client maybe started twice due to first timeout, but that’s acceptable. But if you have another even more simple solution, welcome.

Ralf.