NAME
nos-tun – implement ``nos'' or ``ka9q'' style IP over IP tunnel
SYNOPSIS
nos-tun -t tunnel -s source -d destination -p protocol_number [source] target
DESCRIPTION
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 FreeBSD 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.
EXAMPLES
This end, a FreeBSD 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
HISTORY
The nos-tun utility appeared in FreeBSD 3.0.
AUTHORS
Nickolay N. Dudorov ⟨[email protected]⟩ wrote the program, Poul-Henning Kamp ⟨[email protected]⟩ wrote the man-page. Isao SEKI ⟨[email protected]⟩ added a new flag, IP protocol number.
BUGS
We do not allow for setting our source address for multihomed machines.