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 FreeBSD 3.0 14.Sh NAME 15.Nm nos-tun 16.Nd implement ``nos'' or ``ka9q'' style IP over IP tunnel 17.Sh SYNOPSIS 18.Nm nos-tun 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 29.Nm Nos-tun 30is used to establish an 31.Em nos 32style tunnel, (also known as 33.Em ka9q 34or 35.Em IP-IP 36tunnel) using a 37.Xr tun 4 38kernel interface. 39.Pp 40.Ar Tunnel 41is the name of the tunnel device 42.Pa /dev/tun0 43for example. 44.Pp 45.Ar Source 46and 47.Ar destination 48are the addresses used on the tunnel device. 49If you configure the tunnel against a cisco router, use a netmask of 50.Dq 255.255.255.252 51on the cisco. This is because the tunnel is a point-to-point interface 52in the 53.Bx Free 54end, a concept cisco doesn't really implement. 55.Pp 56.Ar Protocol number 57sets tunnel mode. Original KA9Q NOS uses 94 but many peoples use 4 58in worldwide backbone of ampr.org. 59.Pp 60.Ar Target 61is the address of the remote tunnel device, this must match the source 62address set on the remote end. 63.Sh EXAMPLES 64This end, a 65.Bx Free 66box on address 192.168.59.34: 67.Bd -literal -offset indent 4m 68nos-tun -t /dev/tun0 -s 192.168.61.1 -d 192.168.61.2 192.168.56.45 69.Ed 70.Pp 71Remote cisco on address 192.168.56.45: 72.Bd -literal -offset indent 4m 73interface tunnel 0 74ip address 192.168.61.2 255.255.255.252 75tunnel mode nos 76tunnel destination 192.168.59.34 77tunnel source 192.168.56.45 78.Ed 79.Sh BUGS 80We don't allow for setting our source address for multihomed machines. 81.Sh AUTHORS 82.An Nickolay N. Dudorov Aq nnd@itfs.nsk.su 83wrote the program, 84.An Poul-Henning Kamp Aq phk@FreeBSD.org 85wrote the man-page. 86.An Isao SEKI Aq iseki@gongon.com 87added a new flag, IP protocol number. 88