By default, /etc has the following files: 
/etc/services /etc/protocols /etc/passwd /etc/netconfig /etc/master.passwd /etc/group /etc/dhcpd.conf /etc/rc.subr /etc/rc.router /etc/rc.conf /etc/myname /etc/ipnat.conf /etc/ipf.conf /etc/ifconfig.xxx0 /etc/hosts /etc/syslog.conf
The usage of this file is the same as usual NetBSD. See "NetBSD Documentation" for more details.
Check these files at leaset:
/etc/dhcpd.conf /etc/rc.conf /etc/ipnat.conf /etc/ipf.conf /etc/ifconfig.$interface_name /etc/syslog.conf
See "conf/1.5/etc/" in fdgw source if you compile fdgw on NetBSD 1.5 stable. Some files, e.g. services, protocols et. al. are not included in fdgw source. These are taken from /usr/src/.
Copyright (C) 1993-2017 Ken'ichi Fukamachi mail:< fukachan at fml.org >