GRE Tunnel on OpenWRT 24.10.5

Installing and Using OpenWrt Network and Wireless Configuration
1

GRE Tunnel

I am trying to set up a standard Site-to-Site GRE tunnel between two identical routers bridging two LANs. The routers are running a custom build of OpenWrt 24.10.5.

No matter how I configure the tunnel via LuCI or /etc/config/network, the custom GRE interface never comes UP. I have tried everything I found on the internet and nothing worked yet.

Here is my topology:

Router 1 (Site A):

	Physical Transport IP (eth1): 10.0.0.31
	LAN Subnet: 192.168.102.0/24
	Desired GRE Tunnel IP: 192.168.40.1
	
Router 2 (Site B):

	Physical Transport IP (eth1): 10.0.0.32
	LAN Subnet: 192.168.101.0/24
	Desired GRE Tunnel IP: 192.168.40.3

The Configuration (Router 1)

Here is my /etc/config/network snippet.

	config interface 'gre_tunnel001'
		option proto 'gre'
		option peeraddr '10.0.0.32'
		option ipaddr '10.0.0.31'

config interface 'gre_static001'
	option proto 'static'
	option device '@gre_tunnel001'
	option ipaddr '192.168.40.1'
	option netmask '255.255.255.252'

config route
	option interface 'gre_static001'
	option target '192.168.101.0/24'
	option gateway '192.168.40.3'`

Any guide or guidance is greatly appreciated!

2

Please post all the relevant parts of the network config.

Is gre allowed in the firewall on the incoming zone?

Remember to also set mtu later when the tunnel comes up.

Do you see any error or warning messages in the syslog?

3

Hey mate, really appreciate the help! Funny enough, just while grabbing the details to answer you, I realized where my logic is flawed. Got it working now! Thanks man, have a nice life!