Firstly, I'm very sorry because not posting in this blog for along time. This is because I'm quite busy for the ISO preparation in my company.
This is the how to for NIC bridging on OpenBSD:
1. Make sure you know what is your ethernet card by your OS such as eth0, em0 or etc. To look just use this command
ifconfig -a
2. For example you NIC is em0 and em1.
3. Create the file name hostname.em0, hostname.em1 and bridgename.bridge0 in /etc directory
4. Put word up in hostname.em0 and hostname.em1. Put sentence add em0 add em1 up in bridgename.bridge0.
5. restart you network by command
sh /etc/netstart
6. Finish
Easy right? Enjoy!