# Duplicate MAC Addresses

If you encounter an issue with certain components installed on your computer, such as Fortinet, that assign the same MAC address to all machines, this causes a problem in Medulla where the machines do not register in the correct entities and are reported in GLPI with a UUID that already exists for another machine:

In the file /etc/pulse-xmpp-agent-substitute/registeryagent.ini.local

add the following section and information, ensuring you use the correct case.

```
[parameters]
blacklisted_mac_addresses = 00\:00\:00\:00\:00\:00, 00\:09\:0f\:aa\:00\:01
```

In /etc/pulse-xmpp-agent-substitute/registeryagent.ini.local, add the MAC addresses to be blacklisted

00\\:00\\:00\\:00\\:00\\:00 must be present  
Colons must be escaped, and addresses must be separated by commas