I am getting a Firewall message that says...

According to this,

Well known TCP and UDP ports used by Apple software products

port 445 is for a Microsoft domain server. So it looks like some microsoft software is trying to "call home" for some reason.

If I saw that on my machine I would block it or not let it through. I don't permit stuff communicating with third parties unless I am aware of what it is and why it is happening.

Of course, out of curiousity I would also google "Common Internet File System" to see what that means in case I decide to let it through.

FWIW, one of those google search hits found this. So you know what microsoft stuff you are using and thus you have decide whether to let it though. YOu could be concervative, and block it and see what "breaks" if anything. You could always decide to unblock it later if necessary.

I am not sure but I would think it's got to be something related to microsoft stuff. Another reason to probably not let it though.😉

Since "this one is for the PRO's", and I'm not a PRO (or even a PRO's), I won't breathe a word.

I might've said that CIFS is practically the same thing as SMB, that the message did not come from the OS (nor from MS Office), and that you probably installed some SMB/CIFS server app, perhaps DAVE or perhaps some software which came with a NAS.

Might've… but I'll keep mum.

Little Snitch. (Edited)

Bill H. wrote:

how do I find out which App is making that call?

Well, you know what you've installed on your machine… so think back.

You can try in Terminal lsof -i and check the listing for the respective port. If that doesn't work, you can try netstat.