Linux has supported many kinds of tunnels, but new users may be confused by their differences and unsure which one is best suited for a given use case. In this article, I will give a brief introduction for commonly used tunnel interfaces in the Linux kernel. There is no code analysis, only a brief introduction to the interfaces and their usage on Linux. Anyone with a network background might be interested in this information. A list of tunnel interfaces, as well as help on specific tunnel configuration, can be obtained by issuing the iproute2 command
ip link help.
This post covers the following frequently used interfaces:
- IPIP Tunnel
- SIT Tunnel
- ip6tnl Tunnel
- VTI and VTI6
- GRE and GRETAP
- GRE6 and GRE6TAP
- ERSPAN and IP6ERSPAN
After reading this article, you will know what these interfaces are, the differences between them, when to use them, and how to create them.
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