1.\" 2.\" ---------------------------------------------------------------------------- 3.\" "THE BEER-WARE LICENSE" (Revision 42): 4.\" <phk@FreeBSD.org> wrote this file. As long as you retain this notice you 5.\" can do whatever you want with this stuff. If we meet some day, and you think 6.\" this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp 7.\" ---------------------------------------------------------------------------- 8.\" 9.\" $FreeBSD$ 10.\" 11.Dd April 11, 1998 12.Dt NOS-TUN 8 13.Os 14.Sh NAME 15.Nm nos-tun 16.Nd implement ``nos'' or ``ka9q'' style IP over IP tunnel 17.Sh SYNOPSIS 18.Nm 19.Fl t 20.Ar tunnel 21.Fl s 22.Ar source 23.Fl d 24.Ar destination 25.Fl p 26.Ar protocol_number 27.Ar target 28.Sh DESCRIPTION 29The 30.Nm 31utility is used to establish an 32.Em nos 33style tunnel, (also known as 34.Em ka9q 35or 36.Em IP-IP 37tunnel) using a 38.Xr tun 4 39kernel interface. 40.Pp 41.Ar Tunnel 42is the name of the tunnel device 43.Pa /dev/tun0 44for example. 45.Pp 46.Ar Source 47and 48.Ar destination 49are the addresses used on the tunnel device. 50If you configure the tunnel against a cisco router, use a netmask of 51.Dq 255.255.255.252 52on the cisco. 53This is because the tunnel is a point-to-point interface 54in the 55.Fx 56end, a concept cisco doesn't really implement. 57.Pp 58.Ar Protocol number 59sets tunnel mode. 60Original KA9Q NOS uses 94 but many people use 4 61on the worldwide backbone of ampr.org. 62.Pp 63.Ar Target 64is the address of the remote tunnel device, this must match the source 65address set on the remote end. 66.Sh EXAMPLES 67This end, a 68.Fx 69box on address 192.168.59.34: 70.Bd -literal -offset indent 71nos-tun -t /dev/tun0 -s 192.168.61.1 -d 192.168.61.2 192.168.56.45 72.Ed 73.Pp 74Remote cisco on address 192.168.56.45: 75.Bd -literal -offset indent 76interface tunnel 0 77ip address 192.168.61.2 255.255.255.252 78tunnel mode nos 79tunnel destination 192.168.59.34 80tunnel source 192.168.56.45 81.Ed 82.Sh BUGS 83We don't allow for setting our source address for multihomed machines. 84.Sh AUTHORS 85.An -nosplit 86.An Nickolay N. Dudorov Aq nnd@itfs.nsk.su 87wrote the program, 88.An Poul-Henning Kamp Aq phk@FreeBSD.org 89wrote the man-page. 90.An Isao SEKI Aq iseki@gongon.com 91added a new flag, IP protocol number. 92