I'm sorry if this isn't where I should post this. I'm new to Microtik products. I installed a Routerboard router, and it is working fine except one problem.
I have a few servers running in my lan that are public servers - mail, web and media. These all are accessible from outside through port forwarding. That all works, I forwarded the ports successfully, and the servers are accessible from outside the lan. The problem is that if I'm inside my lan, and try to access the servers using its domain name, I cannot connect to it. Somehow it will not let me connect to the servers using a domain name, which is using, of course, the wan IP.

My previous router didn't block that, so I'm wondering what to change to fix it. I don't even know what it would be called if it was a setting, so I was unsuccessful in my searches for this topic.

Summary: from within my LAN I cannot access servers that are also within my LAN by using their (WAN) domain names)

Thanks in advance!

Set the hairpin nat rule.