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
.Fx end, a concept cisco does not really implement.
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
.Fx 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
.An Nickolay N. Dudorov Aq email@example.com wrote the program,
.An Poul-Henning Kamp Aq phk@FreeBSD.org wrote the man-page.
.An Isao SEKI Aq firstname.lastname@example.org added a new flag, IP protocol number.
We do not allow for setting our source address for multihomed machines.