In http://www.freebsd.org/handbook/handbook167.html, there is a section which reads:

However, FreeBSD's default kernels do not come configured to forward packets (ie, your FreeBSD machine will not act as a router) due to Internet RFC requirements for Internet hosts (see RFC's 1009 [Requirements for Internet Gateways], 1122 [Requirements for Internet Hosts -- Communication Layers], and perhaps 1127 [A Perspective on the Host Requirements RFCs]), so if you want your FreeBSD SLIP Server to act as a router, you will have to add the line

sysctl -w net.inet.ip.forwarding = 0

to your rc.local file.

It seems that the "sysctl -w net.inet.ip.forwarding = 0" line should be corrected to read "sysctl -w net.inet.ip.forwarding = 1", since 0 is the default. I appreciate the effort someone made to update this document, but since my name is still given as the author, I would greatly appreciate it if this were fixed!

Thanks, Guy