In some
<trademark class="registered">Linux
</trademark> distributions, one could look at
<filename>/proc/sys/net/ipv4/ip_forward
</filename> to determine if
<acronym>IP
</acronym> forwarding is enabled. In FreeBSD,
<citerefentry><refentrytitle>sysctl
</refentrytitle><manvolnum>8
</manvolnum></citerefentry> is instead used to view this and other system settings.