Shulou(Shulou.com)06/03 Report--

This article is about how root users can't log in to telnet in linux. If you happen to have the same confusion, you might as well refer to this article. After reading the complete article, I believe you can solve this problem.

Problem found:

1 install = "install the telent service and then start the service before logging in using telent.

This step is normal, there is no accident, partners can go to Baidu to install this telnet service process. I installed it using yum.

2login = "telnet remote login

There is a problem with this step. After the telnet device ip (default port 23), enter the user name and password input interface, and log in using root to prompt Login incorrect all the time. Then I checked the login log. Type the command tail / var/log/secure to view the log as follows:

The last three lines in the log are the information about my last login failure. Look at the penultimate line. Pam_securetty prompts access denied (access denied): tty pts/3 is not secure (terminal pts/3 is not secure).

Logging in to the system also calls the pam module, and login authentication is configured in the / etc/pam.d/login file. It's not surprising to open this file and you'll see a line that contains the pam_securetty.so tag. Then use the man tool to view the man pam_securetty results as follows:

The function is to restrict the login of root users.

The first line of description explains: pam_securetty is a pam module that verifies the login of root users to ensure that the tty (terminal) of root login is secure. So what kind of terminal is secure-as defined by the listing in / etc/securetty (listed in this file is secure).

So combined with the above error log and this explanation, it should be generally clear that the reason for the root login failure is that the terminal "pts/3" is not listed in the / etc/securetty file.

Solution:

So you need to open / etc/securetty and create a new line to add "pts/3" in the original format.

Then restart the telnet service. At this point, root users can log in remotely using telnet.

After reading this article, can you independently solve the problem that root users in linux can't log in to telnet? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel. Thank you for reading.

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