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: src/sbin/nos-tun/nos-tun.8,v 1.6.2.6 2003/02/23 20:53:46 trhodes Exp $ 10.\" 11.Dd September 29, 2016 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. This is because the tunnel is a point-to-point interface 53in the 54.Dx 55end, a concept cisco doesn't really implement. 56.Pp 57.Ar Protocol number 58sets tunnel mode. 59Original KA9Q NOS uses 94 but many people use 4 60in worldwide backbone of ampr.org. 61.Pp 62.Ar Target 63is the address of the remote tunnel device, this must match the source 64address set on the remote end. 65.Sh EXAMPLES 66This end, a 67.Dx 68box on address 192.168.59.34: 69.Bd -literal -offset indent 70nos-tun -t /dev/tun0 -s 192.168.61.1 -d 192.168.61.2 192.168.56.45 71.Ed 72.Pp 73Remote cisco on address 192.168.56.45: 74.Bd -literal -offset indent 75interface tunnel 0 76ip address 192.168.61.2 255.255.255.252 77tunnel mode nos 78tunnel destination 192.168.59.34 79tunnel source 192.168.56.45 80.Ed 81.Sh HISTORY 82The 83.Nm 84utility appeared in 85.Fx 3.0 . 86.Sh AUTHORS 87.An -nosplit 88.An Nickolay N. Dudorov Aq Mt nnd@itfs.nsk.su 89wrote the program, 90.An Poul-Henning Kamp Aq Mt phk@FreeBSD.org 91wrote the man-page. 92.An Isao SEKI Aq Mt iseki@gongon.com 93added a new flag, IP protocol number. 94.Sh BUGS 95We don't allow for setting our source address for multihomed machines. 96