The built-in firewall on macOS is normally not enabled but if it is, it is important to verify that the settings do not block TCP/IP communication with Mimer SQL. Mimer SQL uses TCP/IP port 1360 and that port has to be enabled for traffic through the firewall.


If you have enabled the firewall on macOS the default policy is to block all incoming traffic, but the one explicitly allowed to pass through the firewall. In order to reach Mimer SQL from a client on another machine you therefore have to add Mimer to the list of exclusions, i.e., allow incoming traffic to the Mimer SQL server process. This is done in the following manner:

Open the Security & Privacy preference panel

Security privacy preference panel

Select the Firewall tab, enable changes by authenticating with your password via the padlock icon and then click on the Firewall Options… button

Firewall options

Click the +-icon to add an exclusion to the general blocking principle in the firewall, i.e., add the Mimer network component to the list and give it permission to accept incoming traffic.

Blocking principle

In the following file selection dialogue, press Command-Shift-G to allow entering of an arbitrary path, enter /usr/local/bin and click Go.

File selection dialogue

Then, from the list of programs in /usr/local/bin, select mimtcp and click Add to add it to the list of exclusions


Now is the program that handles incoming TCP/IP request to Mimer SQL allowed


The last thing to do is reboot the computer and then connect to it!


More information about the built-in firewall can be found on Apple’s web site:

The firewall in macOS is, as can be noted from the discussion above, an application firewall, i.e., a firewall where the rules are based on which applications should be allowed access or not. The other way around is a port based firewall where you specify the policy to and from the computer based on ports and addresses. macOS has such a firewall too, called Packet Filter or pf for short, which is very powerful but can only be administered from the command line on a stock macOS installation.

If you have the need for a finely granulated firewall policy is pf probably the best way to go and there is a third party GUI application called Murus that can really help in the configuration of pf that we recommend.

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