What if Centos7 always listens to tcp6 or udp6 in 55 environment so that it cannot be used?

This article will explain in detail how Centos7 can not be used because it always monitors tcp6 or udp6 in 55 environment. The content of the article is of high quality, so the editor will share it for you as a reference. I hope you will have some understanding of the relevant knowledge after reading this article.

1.CentOS 's official Wiki provides a way to turn off IPv6 on 7. The English language is as follows

How do I disable IPv6?

Upstream employee Daniel Walsh recommends not disabling the ipv6 module, as that can cause issues with SELinux and other components, but adding the following to / etc/sysctl.conf:

Net.ipv6.conf.all.disable_ipv6 = 1

Net.ipv6.conf.default.disable_ipv6 = 1

To disable in the running system:

Echo 1 > / proc/sys/net/ipv6/conf/all/disable_ipv6

Echo 1 > / proc/sys/net/ipv6/conf/default/disable_ipv6

Or

Sysctl-w net.ipv6.conf.all.disable_ipv6=1

Sysctl-w net.ipv6.conf.default.disable_ipv6=1

Additional note # 1: If problems with X forwarding are encountered on systems with IPv6 disabled, edit / etc/ssh/sshd_config and make either of the following changes:

two。 Cannot use ss after monitoring IPv4 and IPv6 at the same time under IPv4

Method: modify config

Delete "server": ["[:: 0]"]

If vps has only ipv4 address, then listening to both ipv4 and ipv6 in the configuration file will cause an error. It can only be changed to "server": "0.0.0.0".

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