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This article will explain in detail the example analysis of the restrictions on network interface names in linux. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

Each network interface in Linux has a name, and you can use the ifconfig command to query the interface in the current system.

Are there any requirements or restrictions when naming these interfaces, such as format or length restrictions?

On the surface, there seems to be no restriction that you can name it at will, and it can work well in general application scenarios, but there will be inexplicable problems because of the interface name in special applications.

Problem 1: interface name length is too long

Application scenario: you need to specify a network interface when you use network packet creation and delivery tools to send packets out (such as mz tool).

Problem: a packet failure occurs when the length of this interface name is too long.

Reason: look at the following code.

From standard linux source code (include/linux/socket.h) struct sockaddr {sa_family_t sa_family; / * address family, AF_xxx * / char sa_data [14]; / * 14 bytes of protocol address * /}

When the application uses socket to send packets to the kernel, it will call the struct sockaddr structure to set the protocol family (sa_family) and interface name (sa_data [14]). When the specified interface name is more than 13 bytes, such as a bridge interface name of br-0123456789abcd, the interface name eventually saved in sa_data [14] will be truncated to br-0123456789, so that the package will fail because the interface does not exist.

This is the end of the article on "sample Analysis of Network Interface name restrictions in linux". I hope the above content can be helpful to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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