What protocols are supported over IP by the Linux ip forwarding?

ChrisAbela · 12-03-2021, 08:05 AM

I need to route particular OSI protocols (CLNP and IDRP) over IP on a Linux router. My router works fine for TCP but it does not seem to work for these required protocols.

I looked at net/ipv4/ip_forward.c in the Linux kernel and it appears that only TCP, UDP and ICMP were foreseen, but I am not sure if I am looking at the right file.

I suspect that I would need to set up a VPN to route my data.

I would appreciate any hints you could provide.

smallpond · 12-03-2021, 11:09 AM

CLNP is not IP, so IP forwarding doesn't seem like the right place. IP forwarding only affects packets going through the TCP/IP networking stack. A VPN should work because the packets will be encapsulated in IP packets.

ChrisAbela · 12-04-2021, 01:02 AM

Clearly CLNP is not IP.

I have CLNP stacked over IP. I also have IDRP stacked over IP. I don't have TCP or UDP. I have CLNP or IDRP directly on IP.

Is the Linux IP forwarding restricted at the Transport Layer to TCP, UDP and ICMP. Are there alternatives that do not impose restrictions on the choice of what I stack over IP?