NOS-TUN(8) BSD System Manager's Manual NOS-TUN(8)NAMEnos-tun — implement ``nos'' or ``ka9q'' style IP over IP tunnel
SYNOPSISnos-tun-t tunnel -s source -d destination -p protocol_number [source]
The nos-tun utility is used to establish an nos style tunnel, (also known
as ka9q or IP-IP tunnel) using a tun(4) kernel interface.
Tunnel is the name of the tunnel device /dev/tun0 for example.
Source and destination are the addresses used on the tunnel device. If
you configure the tunnel against a cisco router, use a netmask of
“255.255.255.252” on the cisco. This is because the tunnel is a point-
to-point interface in the FreeBSD end, a concept cisco does not really
Protocol number sets tunnel mode. Original KA9Q NOS uses 94 but many
people use 4 on the worldwide backbone of ampr.org.
Target is the address of the remote tunnel device, this must match the
source address set on the remote end.
This end, a FreeBSD box on address 192.168.59.34:
nos-tun-t /dev/tun0 -s 192.168.61.1 -d 192.168.61.2 192.168.56.45
Remote cisco on address 192.168.56.45:
interface tunnel 0
ip address 192.168.61.2 255.255.255.252
tunnel mode nos
tunnel destination 192.168.59.34
tunnel source 192.168.56.45
Nickolay N. Dudorov ⟨firstname.lastname@example.org⟩ wrote the program, Poul-Henning
Kamp ⟨phk@FreeBSD.org⟩ wrote the man-page. Isao SEKI ⟨email@example.com⟩
added a new flag, IP protocol number.
We do not allow for setting our source address for multihomed machines.
BSD April 11, 1998 BSD