diff --git a/docs/tunneling/iptunnel.md b/docs/tunneling/iptunnel.md index 468a7a5..3eaee1f 100644 --- a/docs/tunneling/iptunnel.md +++ b/docs/tunneling/iptunnel.md @@ -74,7 +74,13 @@ ip link add type vxlan id remote local dstpor Tunnels at Layer 3 (IP level) can be problematic. For example, NATs or firewalls can drop the packets. To work around this, it is possible to encapsulate the encapsulated packets again into a UDP packet. For this you can use either FOU or GUE. With FOU you have to specify the protocol to be encapsulated manually, but FOU does not need an extra header. With GUE you don't have to specify the protocol, GUE uses its own header. -Keep in mind that the more tunnel mechanisms are used, the more headers are generally used. This leads to a reduction in MTU. This means that less data can be transmitted per packet. A high MTU is therefore desirable. +Keep in mind that the more tunnel mechanisms are used, the more headers are generally used. This leads to a reduction in MTU. This means that less data can be +transmitted per packet. A high MTU is therefore desirable. + +The currently used ports can be displayed with the following command: +``` +ip fou show +``` If you get the following error message, you can try to load the FOU kernel module: ```