IP-tunnel using GRE

[Egbert]

I'm considering getting a static public IP range on my home connection with a dynamic IPv4 address. The provider I'm looking at is offering this using a GRE tunnel. Is there any way to configure this on AsusWRT-Merlin firmware on my RT-AC87U?

Their instructions for doing so on DD-WRT are:

insmod ip_gre
ip tunnel add gre0 mode gre local <your public IP> remote <Providers public IP> ttl 225
ip addr add XXX.XXX.XXX.XXX/29 dev gre0

However, when I run these commands on the router using SSH, I get the following error:

insmod: 'ip_gre.ko': module not found
add tunnel gre0 failed: No such device

Is GRE-tunnel functionality not available on this firmware's kernel? I thought it must be since L2TP VPN also uses GRE as far as I know. Is there any way to work around this?

 

[kvic]

@Egbert you need to compile your own firmware to get the GRE module. Particularly set CONFIG_NET_IPGRE=m before compile.

Interesting read of GRE use in your situation btw.

 

[Egbert]

Thank you for your reply. Recompiling the kernel for my router is not really on the top of my priority list at this moment. Is there any reason not to enable this feature in the kernel for all routers / compile it as a module? It seems like a really relevant module to the scope of router functionality.

I'll try to find a different working solution (like GRE passthru to another host) for the time being and hope that this module will be enabled in future releases of the firmware.

 

[RMerlin]

Thank you for your reply. Recompiling the kernel for my router is not really on the top of my priority list at this moment. Is there any reason not to enable this feature in the kernel for all routers / compile it as a module? It seems like a really relevant module to the scope of router functionality.

I'll try to find a different working solution (like GRE passthru to another host) for the time being and hope that this module will be enabled in future releases of the firmware.

I do as little changes as possible to the kernel, as any change can potentially prevent the closed source modules from loading. This was the reason for instance why I had to drop IPSEC support when the Trend Micro DPI engine was added.