Hello together,

I have checked the forum but did not find any case fitting my one.
I would like to assign an IP-address to a device PC1 on port "ether4" depending on the device connected to port "ether5" (PC2 or PC3). I wrote a script but it does not work (RouterOS 7.13.3):

:local macaddress5 [[:pick [/interface ethernet find where name="ether5"] 1 18]]
:local ipaddress

:log info ("MAC Address on ether5: " . $macaddress5)

:if ($macaddress5 = "MAC-OF_PC2") do={
:set ipaddress "10.150.2.1"
:log info ("Setting IP Address to: " . $ipaddress)
} else={
:if ($macaddress5 = "MAC-OF_PC3") do={
:set ipaddress "192.168.11.234"
:log info ("Setting IP Address to: " . $ipaddress)
} else={
:set ipaddress "192.168.88.130"
:log info ("Setting IP Address to: " . $ipaddress)
}
}

/ip dhcp-server lease set [find where mac-address="MAC-OF-PC1"] address=$ipaddress

The script is neither able to get the MAC-address of the device connected to port "ether5" ($macaddress5 is empty), nor assigns the (default) IP-address "192.168.88.130" to PC1 on "ether4".
PC1 = notebook, PC2 and PC3 = embedded hardware. Notebook and embedded HW communicate via SW simulator/webbrowser, which is why a certain IP-address of PC1 is needed....

Thanks!

First of all, i would just like to know how to extract the mac-address of a device connected to port 5 by scripting. The command "/ip arp print as-value where address="192.168.88.253"" returns at least a list of data including the mac-address of the connected device. I need to detail this command in order to only extract the mac-address of the connected device (PC2 or PC3) and assign it to a variable.

A hint: the IP-addresses of devices PC2 and PC3 will always be static!

Got it! Searching for device PC2 via static IP address (arp entries!) and assigning an IP address to device PC1 accordingly:

/ip arp remove [ find where !complete ]

:local ipAddress "IP-ADDRESS-OF-PC2";
:local arpId [/ip arp find address=$ipAddress];
:local newIPAddress;

:log info ("Checking ARP entry for IP Address: " . $ipAddress);
:log info ("Result of /ip arp find ID: " . $arpId);

:if ($arpId != "") do={
:local macAddress [/ip arp get $arpId mac-address];
:log info ("ARP Entry found for IP Address: " . $ipAddress);
:log info ("MAC Address: " . $macAddress);

:if ($macAddress = "MAC-ADDRESS-OF-PC2") do={
:set newIPAddress "IP-ADDRESS-1";
} else={
:if ($macAddress = "MAC-ADDRESS-OF-PC3") do={
:set newIPAddress "IP-ADDRESS-2";
} else={
:set newIPAddress "IP-ADDRESS-3";
}
}
} else={
:log info ("ARP entry not found for IP Address: " . $ipAddress);
:set newIPAddress "IP-ADDRESS-3";
:log info ("ARP Table Contents:");

:local arpEntries [/ip arp find]

:foreach arpEntryId in=$arpEntries do={
:local ipAddressE [/ip arp get $arpEntryId address]
:log info " IP Address: $ipAddressE"
}
}
:log info ("Setting IP Address to: " . $newIPAddress);
/ip dhcp-server lease set [find where mac-address="MAC-ADDRESS-OF-PC1"] address=$newIPAddress;

}

Remove the "static" line ":local ipAddress "IP-PC2";" and create a list of different IP addresses instead to make the code more flexible.

BR

Could you not just assign the IPs to ether5 and use src-nat without having to script or even change the Notebook IP?