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 August 23, 2018 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 s 20.Ar source 21.Fl d 22.Ar destination 23.Fl p 24.Ar protocol_number 25.Ar target 26.Sh DESCRIPTION 27The 28.Nm 29utility is used to establish an 30.Em nos 31style tunnel (also known as 32.Em ka9q 33or 34.Em IP-IP 35tunnel) using a 36.Xr tun 4 37kernel interface. 38.Pp 39.Ar Source 40and 41.Ar destination 42are the addresses used on the tunnel device. 43If you configure the tunnel against a cisco router, use a netmask of 44.Dq 255.255.255.252 45on the cisco. This is because the tunnel is a point-to-point interface 46in the 47.Dx 48end, a concept cisco doesn't really implement. 49.Pp 50.Ar Protocol number 51sets tunnel mode. 52Original KA9Q NOS uses 94 but many people use 4 53in worldwide backbone of ampr.org. 54.Pp 55.Ar Target 56is the address of the remote tunnel device, this must match the source 57address set on the remote end. 58.Sh EXAMPLES 59This end, a 60.Dx 61box on address 192.168.59.34: 62.Bd -literal -offset indent 63nos-tun -s 192.168.61.1 -d 192.168.61.2 192.168.56.45 64.Ed 65.Pp 66Remote cisco on address 192.168.56.45: 67.Bd -literal -offset indent 68interface tunnel 0 69ip address 192.168.61.2 255.255.255.252 70tunnel mode nos 71tunnel destination 192.168.59.34 72tunnel source 192.168.56.45 73.Ed 74.Sh HISTORY 75The 76.Nm 77utility appeared in 78.Fx 3.0 . 79.Sh AUTHORS 80.An -nosplit 81.An Nickolay N. Dudorov Aq Mt nnd@itfs.nsk.su 82wrote the program, 83.An Poul-Henning Kamp Aq Mt phk@FreeBSD.org 84wrote the man-page. 85.An Isao SEKI Aq Mt iseki@gongon.com 86added a new flag, IP protocol number. 87.Sh BUGS 88We don't allow for setting our source address for multihomed machines. 89