We just upgrade to a new MX100 form a MX80, we have a few VLANs working and we adding a new server to act as an AD domain controller, we are using Meraki as a DHCP and DNS server, trying to keep it simple, under DHCP options we add the IP of the AD Server so they can be add it to the domain, but the problems is that the network slows down and the credit card machines can not communicate outside the network, has anyone have any suggestions.
I assume you mean you have added the AD controller as a DNS server under DHCP.
I would try running a DNS query against the AD controller and make sure it can resolve queries properly.
Under DHCP Tab DNS nameservers, Custom nameservers I add the AD IP and Merki IP local IP. It works but the network slows down and credit card machine won't communicate
Did the slow down happen after you added the MX100, or after you added the AD controller? Which one of the two changes resulted in the slow down?
I understand MX do not offer DNS Services Adding MX Local IP in DHCP NS List shall not be of any help.
Hope your AD DNS server is working good to resolve domains.
You may follow @PhilipDAth instructions on this.
Also consider verifying L3 L7 Content Filtering Traffic Shaping rules and Firmware version.