first, thanks for you reply and sorry for my very late response
actually, I'm using the OpenWrt as the gateway and it works fine (NAT+port forwarding, the OpenWrt is built by linux and using the iptables)
I'd like to change the OpenBSD as it can take care huge traffic loading
In fact, I copy the official example
(
https://www.openbsd.org/faq/pf/example1.html)
and did few modifications.
It worked except that the INSIDER cannot connect to the internal webserver
However, for the currect OpenWrt, it works perfectly.
That means, for the OUTSIDER, it works
For the INSIDER, it DOES NOT work for both internal and external IP address of the webserver
That why I think, it's not the internal network problem or name resolving problem.
My questions are:
1) anyone using the offical example got the same problem as mine?
2) how to modify the pf.conf and get the problem solved?
thanks